UC-NRLF 


QD 

/JO 

;  —  SB    35 

(L  (*    MANGAN 


;R  SUPPLIES 


BY 


HARRY  PEACH  CORSON 

B.  S.  New  Hampshire  College,  1910 
M.  S.  University  of  Illinois,  1912 


THESIS 

Jf 

Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 

Degree  of 

DOCTOR  OF  PHILOSOPHY 
IN  CHEMISTRY 


IN 


THE  GRADUATE  SCHOOL 


OF  THE 


UNIVERSITY  OF  ILLINOIS 


1915 


EXCHANGE 


MANGANESE  IN  WATER  SUPPLIES 


BY 


HARRY  PEACH  CORSON 
\\ 

B.  S.  New  Hampshire  College,  1910 
M.  S.  University  of  Illinois,  1912 


THESIS 

Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 

Degree  of 

DOCTOR  OF  PHILOSOPHY 
IN  CHEMISTRY 


•/w- 

THE  GRADUATE  SCHOOL 

OF  THE 

UNIVERSITY  OF  ILLINOIS 
1915 


ACKNOWLEDGMENT 

This  investigation  was  carried  out  under  the  direction  of  Dr. 
Edward  Bartow,  professor  of  sanitary  chemistry  in  the  University 
of  Illinois  and  Director  of  the  Illinois  State  Water  Survey.  The 
writer  wishes  to  express  his  gratitude  to  Professor  Bartow  for  the 
helpful  suggestions  received  and  the  kindly  interest  shown  during 
the  progress  of  the  work. 


CONTENTS 

Page. 

Acknowledgment     2 

Introduction    5 

Determination  of  manganese  in  water 5 

Previous  investigations 5 

Experimental    studies    7 

Preparation   of  solutions 7 

The  lead-peroxide  method 9 

The   sodium-bismuthate  method 15 

The  persulphate  method 19 

Comparison  of  three  colorimetrie  methods 23 

Eelative  value  of  colorimetrie  methods 24 

Manganese  in  water  supplies 25 

General  occurrence  25 

Methods  of  analysis 28 

Manganese   28 

Iron     29 

Dissolved  solids    29 

Manganese  in  waters  of  Illinois 29 

Wells  in  Potsdam  sandstone 29 

Wells  in  St.  Peter  sandstone 29 

Wells  in  limestone 31 

Wells  in  unconsolidated  deposits 31 

Springs 35 

Coal-mine  drainage    36 

Elvers  and  lakes 37 

Summary 38 

Eemoval  of  manganese  from  water  supplies 39 

Methods    39 

Manganese  permutit    44 

Sand  filtration 48 

Manganese-removal  plants  in  Illinois 54 

Eemoval  of  manganese  at  Anna 54 

Eemoval  of  manganese  at  Mount  Vernon 60 

Incrustation  of  water  pipes  by  manganese-bearing  waters 62 

Conclusion    64 

Vita  .  .   66 


3605 


ILLUSTRATIONS 

Page.' 
Figure  1.     Map  of  Illinois  showing  occurrence  of  manganese  in  water  from 

wells  in  unconsolidated   deposits 34 

2.     Experimental  sand  filters  for  the  removal  of  manganese 48 


MANGANESE  IN  WATER  SUPPLIES 
By  H.  P.  Corson. 

INTRODUCTION 

Water  supplies  containing  manganese  have  been  considered  un- 
common in  the  United  States,  and  determinations  of  manganese  are 
made  in  but  few  laboratories  as  a  part  of  the  general  routine  work  of 
water  analysis.  Even  in  the  selection  of  a  water  supply  for  a  com- 
munity the  content  of  manganese  is  seldom  considered.  In  April, 
1911,  the  attention  of  the  Illinois  State  Water  Survey  was  called  to 
a  serious  incrustation  which  had  formed  in  the  city  water  system  of 
Mount  Vernon,  Illinois.1  An  analysis  showed  that  this  incrustation 
contained  4.4  to  8.8  per  cent  and  that  the  original  water  contained 
0.6  part  per  million  of  manganese.  Manganese  was  found  later,  in  a 
number  of  other  water  supplies  both  public  and  private,  of  the  State. 

Manganese  in  a  water  supply  is  objectionable  because  it  deposits 
in  water  pipes  a  dark  incrustation,  which  in  some  pipes  is  so  extensive 
as  to  cause  complete  stoppage.  It  stains  plumbing  fixtures  a  dark 
color  due  to  the  separation  of  the  dioxide.  It  also  stains  fabrics  yellow 
or  brown  when  water  containing  it  is  used  in  the  laundry.  In  these 
respects  waters  containing  manganese  resemble  those  which  contain 
iron,  but  the  deposits  are  darker  and  more  difficult  to  remove  than 
those  produced  by  waters  which  contain  iron.  The  present  investiga- 
tion was  undertaken  on  account  of  the  economic  importance  of  this 
subject.  The  problem  has  been  studied  from  the  standpoints  of  the 
quantitative  determination  of  manganese,  its  occurrence  and  distribu- 
tion in  natural  waters,  and  its  removal  from  water  supplies. 

DETERMINATION  OF  MANGANESE  IN  WATER 
Previous  Investigations 

Theoretically,  it  might  seem  that  any  accurate  method  for  the 
determination  of  manganese  in  substances  could  be  successfully  ap- 
plied to  the  determination  of  the  element  in  water.  Many  methods 
are,  however,  wholly  impracticable.  Manganese  occurs  in  water  in 
relatively  small  amounts,  usually  only  a  small  fraction  of  a  milligram 

1  Corson,  H.  P.,  Occurrence  of  manganese  in  the  water  supply  and  in  an  incrustation  in 
the  water  mains  at  Mount  Vernon,  Illinois:  Illinois  Univ.  Bull.,  Water-Survey  Series  10, 
57-65  (1913). 

5 


*'s      "*   •     »°  w  i  « 

6  .MANGANESE  IN  WATER  SUPPLIES 

per  liter.  In  some  waters  several  milligrams  per  liter  are  found,  but 
those  in  which  more  than  10  milligrams  per  liter  of  the  element  are 
encountered  are  very  uncommon.  Most  other  salts  are  present  in  nat- 
ural waters  in  amounts  many  times  as  great  as  the  salts  of  manganese. 
These  conditions  eliminate  some  of  the  accurate  standard  gravimetric 
and  volumetric  methods  for  the  determination  of  manganese.  If  they 
are  used,  under  most  conditions,  large  volumes  of  water  must  be  evap- 
orated in  order  to  procure  a  sufficient  quantity  of  the  element  for  de- 
termination. In  complete  analysis  of  the  mineral  content  of  water 
samples  these  procedures  may  not  be  seriously  objectionable,  but  in 
rapid  work,  such  as  the  analytical  control  of  a  manganese-removal 
plant,  they  would  be  wholly  impracticable. 

Several  water  analysts  have  recommended  volumetric  or  gravi- 
metric methods  for  manganese. 

Liihrig  and  Becker1  report  satisfactory  results  in  applying 
Knorre  's2  persulphate  peroxide  method  to  the  determination  of  man- 
ganese in  water.  If  the  water  contains  less  than  10  milligrams 
per  liter  of  manganese,  however,  they  state  that  it  must  be  con- 
centrated by  evaporation.  Klut3  also  recommends  the  same  method 
for  waters  whose  content  of  manganese  is  more  than  10  milligrams 
per  liter.  He  states,  however,  that  5  to  10  liters  of  the  sample  should 
be  used.  Prescher4  recommends  that  the  manganese  be  precipitated 
with  potassium  chlorate  from  a  one-liter  sample  as  manganese  dioxide 
after  concentration  with  nitric  acid.  The  precipitated  manganese 
dioxide  is  then  dissolved  in  standard  oxalic  acid,  the  excess  of  which 
is  determined  by  titrating  with  potassium  permanganate.  He  states 
that  the  amount  of  manganese  found  must  be  increased  by  10  per 
cent  in  order  to  give  a  correct  value.  Noll5  precipitates  the  manga- 
nese as  the  dioxide  in  an  ammoniacal  solution  with  bromine  water. 
This  precipitate  is  then  treated  with  hydrochloric  acid  and  potassium 
iodide,  and  the  liberated  iodine  is  titrated  with  sodium  thiosulphate. 
Results  which  were  in  good  agreement  with  the  theoretical  values  were 
obtained  on  some  artificially  prepared  manganese  waters.  The  volume 
of  sample  used  was  500  cubic  centimeters.  All  these  methods,  how- 
ever, have  found  little  favor  and  colorimetric  methods  are  in  general 
use.  Colorimetric  methods  for  the  determination  of  manganese  de- 

JLuhrig,  fl.,  and  Becker,  W.,  Zur  Bestimmung  des  Mangans  im  Trinkwasser :  Pharm. 
Zentralhalle,  48,  137-42  (1907). 

fKnorre,  G.  von,  Ueber  eine  neue  Methode  zur  Manganbestimmung :  Z.  angew.  Chem.,  14, 
1149-62  (1901). 

8Klut,  H.,  Nachweis  und  Bestimmung  von  Mangan  im  Trinkwasser:  Mitt.  kgl.  Pru- 
fungsamt.  Wassersorg.  Abwasserbeseit.,  12,  182-94  (1909). 

*Prescher,  Johannes,  Zur  Bestimmung  des  Mangans  im  Trinkwasser:  Pharm.  Zentral- 
halle, 47,  799-802  (1906). 

*Noll,  H.,  Manganbestimmung  in  Trinkwasser :  Z.  angew.  Chem.,  20,  490-2   (1907). 


PREPARATION  OF  SOLUTIONS  7 

pend  on  oxidation  of  the  manganous  salt  to  permanganate  and  com- 
parison of  the  color  produced  thereby  with  standards  of  known  con- 
tent of  permanganate.  Three  oxidizing  agents,  lead  peroxide  (Pb02), 
sodium  bismuthate  (NaBi03),  and  ammonium  persulphate  ((NH4)2 
S208)  have  been  used  for  the  oxidation. 

The  committee  on  standard  methods  of  water  analysis1  permits 
use  of  the  bismuthate  and  the  lead-peroxide  methods  for  the  determi- 
nation of  amounts  of  manganese  less  than  10  milligrams  per  liter  but 
recommends  Knorre's2  volumetric  persulphate  method  if  more  than 
that  amount  is  present. 

In  the  Bureau  of  Chemistry,  U.  S.  Department  of  Ag- 
riculture3, the  colorimetric  persulphate  method  is  used.  It  was  found 
on  inquiry,  that  no  water  chemists  use  the  lead-peroxide  method.  As 
several  methods  are  used  for  determining  manganese  in  water  and 
some  literature  has  accumulated  concerning  their  accuracy  and 
sources  of  error  it  seemed  advisable  to  make  a  careful  comparison  of 
them  for  the  proposed  revision  of  the  report  of  the  committee  on 
standard  methods  of  water  analysis.4  Accordingly  the  lead-peroxide 
method,  the  sodium-bismuthate  method,  and  the  ammonium-persul- 
phate method  were  carefully  compared. 

Experimental  Studies 
PREPARATION  OF  SOLUTIONS 

Solutions  of  manganous  chloride,  potassium  permanganate,  and 
manganous  sulphate,  of  known  content  of  manganese  were  prepared. 

Manganous  chloride. — A  standard  solution  of  manganous  chlo- 
ride was  prepared  by  dissolving  approximately  32  grams  of  pure 
manganous  chloride  (MnCl2.4H20)  in  a  liter  of  distilled  water.  To 
obtain  pure  manganous  chloride  a  solution  of  about  200  grams  of 
Baker's  Analyzed  manganous  chloride  in  one  liter  of  distilled  water 
was  boiled  with  a  small  amount  of  manganese  carbonate  prepared  by 
adding  sodium  carbonate  to  a  portion  of  the  original  solution,  filter- 
ing, and  washing  the  precipitate.  Possible  traces  of  iron,  aluminium, 
and  chromium  were  thus  removed.  The  mixture  was  then  filtered, 
after  which  the  filtrate  was  treated  with  ammonium  sulphide  to  re- 
move copper,  lead,  and  other  heavy  metals.  The  solution  was  then 
acidified  with  hydrochloric  acid  and  boiled  to  remove  hydrogen  sul- 

*Standard  methods  for  the  examination  of  water  and  sewage,  Am.  Pub.  Health  Assoc., 
New  York,  2nd  ed.,  49-51   (1912). 

^norre,  G.  von,  Ueber  eine  neue  Methode  zur  Manganbestimmung :  Z.  angew.  Chem.,  14. 
1149-62    (1901). 

3Colorimetric  determination  of  manganese:  in  Proc.  28th  Ann.  conv    Assoc      Off    Agr. 
Chemists,  U.  S.  Agri.  Dept.,  Bur.  Chem.  Bull.  162,  78-79   (1912). 
4To  be  published  in  1916. 


MANGANESE  IN  WATER  SUPPLIES 

phide,  after  which  it  was  filtered.  A  small  amount  of  copper,  which 
was  present,  was  thus  removed.  An  excess  of  sodium  carbonate  was 
next  added,  and  the  manganous  carbonate  was  separated  by  filtration 
and  washed  free  from  chlorides.  Most  of  this  precipitate  was  then 
dissolved  in  hydrochloric  acid.  A  small  portion  of  that  which  did  not 
dissolve  was  added  to  the  solution,  and  the  mixture  was  boiled  and 
filtered.  Crystalline  manganous  chloride  was  obtained  on  evapora- 
tion. The  chloride  in  the  standard  solution  of  this  was  determined 
gravimetrically,  and  the  amount  of  manganese  was  calculated  from 
that  result.  Manganese  was  also  directly  determined  by  evaporating 
to  dryness  a  50  cubic  centimeter  portion  of  the  solution  with  sulphuric 
acid,  heating,  and  weighing  as  manganous  sulphate.  Gooch  and 
Austin1  have  shown  that  this  method  is  accurate.  The  average  of 
triplicate  determinations  by  each  method  gave  the  following  results: 

By  determining  chlorine  as  silver  chloride  one  cubic  centimeter 
contains  1.604  milligrams  of  chlorine  and  1.245  milligrams  of  man- 
ganese. 

By  determining  manganese  as  manganous  sulphate  one  cubic 
centimeter  contains  1.254  milligrams  of  manganese. 

The  mean  of  these  two  values,  1.250  milligrams  of  manganese, 
was  taken  as  the  strength  of  the  solution,  which  was  then  diluted  to 
one-tenth  of  its  original  strength,  so  that  one  cubic  centimeter  con- 
tained 0.125  milligram  of  manganese. 

Potassium  permanganate. — For  the  preparation  of  standards  of 
permanganate  by  simple  dilution  a  standard  solution  was  prepared 
by  dissolving  in  one  liter  of  water  0.2880  gram  of  Kahlbaum's  potas- 
sium permanganate  that  had  been  crystallized  twice  from  double  dis- 
tilled water  and  dried  over  sulphuric  acid.  The  content  of  one  cubic 
centimeter  of  this  solution  was,  therefore,  assumed  to  be  0.100  milli- 
gram of  manganese. 

Manganous  sulphate. — Dilute  solutions  of  permanganate  are  not 
very  stable.2  In  order  to  check  their  value  and  to  have  standards 
prepared  exactly  as  the  sample  was  treated  0.2880  gram  of  potassium 
permanganate  dissolved  in  water  was  reduced  to  manganous  sulphate 
by  heating  with  sulphuric  acid  and  a  slight  excess  of  oxalic  acid, 
after  which  the  solution  was  diluted  to  one  liter.  One  cubic  centi- 
meter of  this  solution  contained,  therefore,  0.100  milligram  of  manga- 
nese. 


1Gooch,   P.  A.,   and  Austin,  Martha,   Die  Bestiminung  des  Mangans   als   Sulfat  und  als 
Oxyd:   Z.  anorg.  Chem.,   17,  264-71   (1898). 

*Morse,  H.  N.,  Hopkins,  A.  J.,  and  Walker,  M.  S..  The  reduction  of  permanganic  acid 
by  manganese  superoxide:     Am.  Chem.  J.,  18.  401-19    (1896). 


LEAD-PEROXIDE  METHOD  9 

LEAD-PEROXIDE  METHOD 

The  lead-peroxide  method,  first  described  by  Crum1,  has  been 
used  for  a  long  time  in  iron  and  steel  work.  It  has,  however,  been 
used  only  to  limited  extent  in  water  analysis,  and  it  has  been  largely 
supplanted  by  the  bismuthate  and  persulphate  methods.  Of  twelve 
investigators  who  have  worked  on  the  determination  of  manganese  in 
water  during  the  past  ten  years  Klut2  alone  recommends  this  method. 
The  majority  favor  the  persulphate  method  and  the  bismuthate 
method  seems  to  be  second  in  popularity.  No  one,  however,  appears 
carefully  to  have  compared  the  three  methods.  The  material  embodied 
in  the  section  dealing  with  manganese  in  the  report  of  the  commit- 
tee3 appears  to  have  been  based  entirely  upon  the  work  of  Klut2  and 
of  R.  S.  Weston.4 


TABLE  1. — FIRST  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 
THE  LEAD-PEROXIDE  METHOD. 

SOLUTIONS  OF  KNOWN  CONTENT  OF  MANGANOUS  CHLORIDE  IN  DISTILLED  WATER  COM- 
PARED WITH  DILUTE  STANDARD  SOLUTION  OF  POTASSIUM  PERMAGANATE. 


Cubic   centimeters   of   solution. 

Milligrams  of  manganese. 

Manganous 
chloride. 

Standard 
permanganate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical value. 

0.0 

0.0 

0.00 

0.00 

+0.00 

.2 

.0 

.00 

.025 

—  .025 

.2 

.0 

.00 

.025 

—  .025 

.4 

.2 

.02 

.050 

—  .03 

.4 

.2 

.02 

.050 

—  .03 

.6 

.3 

.03 

.075 

—  .045 

.6 

.4 

.04 

.075 

—  .035 

.8 

.7 

:07 

.100 

—  .03 

.8 

.6 

.06 

.100 

—  .04 

1.0 

1.0 

.10 

.125 

—  .025 

1.0 

1.0 

.10 

.125 

—   .025 

1.2 

1.2 

.12 

.150 

—  .03 

1.2 

1.3 

.13 

.150 

—  .02 

1.5 

1.8 

.18 

.187 

—  .007 

1.5 

1.8 

.18 

.187 

—  .007 

2.0 

2.5 

.25 

.250 

-+-   .00 

2.0 

2.3 

.23 

.250 

—  .02 

2.5      . 

2.8 

.28 

.312 

—  .032 

2.5 

2.5 

.25 

.312 

—  .062 

3.0 

3.5 

.35 

.375 

—  .025 

3.0 

3.5 

.35 

.375 

—  .025 

3.5 

4.0 

.40 

.438 

—  .038 

3.5 

4.0 

.40 

.438 

—  .038 

4.0 

4.5 

.45 

.500 

—  .050 

4.0 

5.0 

.50 

.500 

-+-  .000 

Mean    —  .027 

,  Walter,  Empfindliches  Priifungsmittel  auf  Mangan:   Ann.,   55,  219-20    (1845). 

2Klut,  H.,  Nachweis  und  Bestimmung  von  Mangan  im  Trinkwasser:  Mitt.  kgl. 
Priifungsamt.  Wasserversorg.  Abwasserbeseit.,  12,  182-94  (1909). 

'Standard  methods  for  the  examination  of  water  and  sewage,  Am.  Pub.  Health  Assoc  , 
New  York,  2nd  ed.,  49-51  (1912). 

4Weston,  R.  S.,  The  determination  of  manganese  in  water:  J.  Am.  Chem.  Soc.,  29, 
1074-8  (1907). 


10 


MANGANESE  IN  WATER  SUPPLIES 


The  first  series  of  experiments  with  the  lead-peroxide  method 
was  carried  out  according  to  the  following  procedure.  Different 
amounts  of  the  standard  manganous-chloride  solution  were  diluted 
with  distilled  water,  and  evaporated  in  beakers  with  two  or  three 
drops  of  sulphuric  acid  until  white  fumes  appeared.  They  were  then 
diluted  with  water,  acidified  with  10  cubic  centimeters  of  dilute  nitric 
acid  free  from  brown  oxides  of  nitrogen,  boiled  down  to  a  volume  of 
50  cubic  centimeters,  treated  with  0.5  gram  of  lead  peroxide,  and 
boiled  for  five  minutes.  It  was  then  filtered  through  an  asbestos  mat 
in  a  Gooch  crucible,  which  had  been  ignited,  treated  with  permanga- 
nate, and  washed  with  water.  The  filtrate  was  transferred  to  a  Nessler 
tube  and  the  color  was  compared  immediately  with  standards  made  by 
diluting  the  standard  solution  of  potassium  permanganate  with  water 
acidified  with  sulphuric  acid.  The  results,  shown  in  Table  1,  indicate 
that  the  determined  amounts  of  manganese  were  nearly  all  lower  than 
the  amounts  actually  present.  The  mean  difference  in  the  twenty-five 
determinations  was  0.027  milligram. 

In  order  to  check  the  possibility  of  error  due  to  possible  differ- 
ence in  content  of  manganese  between  the  solutions  of  manganous 

TABLE  2. — SECOND  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 

THE  LEAD-PEROXIDE  METHOD. 

SOLUTIONS  OF  KNOWN  CONTENT  OF  POTASSIUM  PERMANGANATE  IN  DISTILLED  WATER 
COMPARED  WITH  DILUTE  STANDARD  SOLUTION  OF  POTASSIUM  PERMANGANATE. 


Cubic  centimeters  of  solution. 

,              Milligrams  of  manganese. 

Potassium 
permanganate. 

Standard 
permanganate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical value. 

0.0 

0.0 

0.00 

0.00 

•+•  .00 

.2 

.0 

.00 

.02 

—  .02 

.2 

.0 

.00 

.02 

—  .02 

.4 

.15 

.015 

.04 

—  .025 

.4 

.10 

.01 

.04 

—  .03 

.6 

.3 

.03 

.06 

—  .03 

.6 

.3 

.03 

.06 

—  .03 

.8 

.4 

.04 

.08 

—  .04 

.8 

.5 

.05 

.08 

—  .03 

1.0 

.8 

.08 

.10 

—  .02 

1.0 

.8 

.08 

.10 

—  •  .02 

1.2 

1.0 

.10 

.12 

—  .02 

1.2 

.9 

.09 

.12 

—  .03 

1.5 

1.2 

.12 

.15 

—  .03 

1.5 

1.2 

.12 

.15 

—  .03 

2.0 

1.8 

.18 

.20 

—  .02 

2.0 

2.0 

.20 

.20 

-t-  .00 

2.5 

2.2 

.22 

.25 

—  .03 

2.5 

2.2    ' 

.23 

.25 

—  .02 

3.0 

2.2 

.22 

.30 

—  .08 

3.0 

2.5 

.25 

.30 

—  .05 

3.5 

3.0 

.30 

35 

—  .05 

3.5 

3.2 

.32 

.35 

—  .03 

4.0 

4.0 

.40 

.40 

-t-  .00 

4.0 

3.7 

.37 

.40 

—  .03 

Mean  

—  .027 

LEAD-PEROXIDE  METHOD 


11 


chloride  and  potassium  permanganate  the  second  series  of  determina- 
tions was  made  with  diluted  portions  of  the  solution  of  potassium 
permanganate  instead  of  the  solution  of  manganous  chloride.  (See 
Table  2).  These  portions  were  treated  like  those  reported  in  Table  1 
and  were  then  compared  with  standards  prepared  from  the  same 
solution  of  potassium  permanganate.  The  average  amount  found  was 
0.027  milligram  less  than  actually  present  although  the  differences 
were  variable.  When  0.00  to  0.10  milligram  of  manganese  is  pres- 
ent the  error  is  as  great  as  50  per  cent.  Though  the  error  is 
only  about  10  per  cent  when  0.3  or  0.4  milligram  is  present  it 
is  still  a  serious  error.  These  results  indicate  that  either  the 
oxidation  to  permanganate  is  incomplete  or  there  is  some  reduc- 
tion in  subsequent  steps,  as  the  color  produced  is  not  so  deep  as  that 
produced  by  a  standard  solution  of  potassium  permanganate  diluted 
to  an  equivalent  content  of  manganese. 

A  third  series  of  determinations  (Table  3)  was,  therefore,  made 
in  which  the  standards  for  comparison  were  made  from  the  solution 
of  manganous  sulphate  treated  in  the  same  manner  as  the  samples 

TABLE  3. — THIRD  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 
THE  LEAD-PEROXIDE  METHOD. 

SOLUTIONS  OF  KNOWN  CONTENT  OP  MANGANOUS  CHLORIDE  IN  DISTILLED  WATER  COM- 
PARED WITH  DILUTE  STANDARD  SOLUTION  OF  MANGANOUS  SUL- 
PHATE TREATED  IN  THE  SAME  MANNER. 


Cubic  centimeters  of  solution. 

Milligrams  of  manganese. 

Manganous 
chloride. 

Standard 
manganous 
sulphate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical value. 

0.0 

0.0 

0.00 

0.00 

+0.00 

.2 

.0 

.00 

.025 

—  .025 

.2 

.0 

.00 

.025 

—  .025 

.4 

.6 

.06 

.050 

+    .01 

.4 

.4 

.04 

.050 

—  .01 

.6 

.8 

.08 

.075 

+    .005 

.6 

.4 

.04 

.075 

—  .035 

.8 

.2 

.12 

.100 

+   .02 

.8 

.5 

.15 

.100 

•f    .05 

1.0 

.1 

.11 

.125 

—  .015 

1.0 

.2 

.12 

.125 

—  .005 

1.2 

.0 

.10 

.150 

—  .05 

1.2 

.1 

.16 

.150 

-r-    .01 

1.5 

2.3 

.23 

.187 

+    .043 

1.5 

2.0 

.20 

.187 

4-    .013 

2.0 

1.8 

.18 

.250 

—  .07 

2.0 

1.9 

.28 

.250 

+   .03 

2.5 

3.0 

.30 

.312 

—  .012 

2.5 

3.2 

.32 

.312 

-f   .008 

3.0 

4.0 

.40 

.375 

+   .025 

3.0 

4.0 

.40 

.375 

-f   .025 

3.5 

3.5 

.35 

.438 

—  .088 

3.5 

4.0 

.40 

.438 

—  .038 

4.0 

5.0 

.50 

.500 

±  .000 

4.0 

6.0 

.60 

.500 

+   .100 

Mean  —  .001 

MANGANESE  IN  WATER  SUPPLIES 


were  treated  on  the  supposition  that  standards  thus  prepared  should 
be  exactly  comparable  with  the  sample.  The  results  obtained  were, 
however,  very  erratic,  some  being  too  high  and  some  too  low.  Even 
when  carried  out  under  conditions  which  were  as  nearly  similar  as 
possible  checks  could  not  be  obtained,  and  the  error  was  as  great  as 
30  per  cent  in  many  tests. 

TABLE  4. — FOURTH  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 
THE  LEAD-PEROXIDE  METHOD. 

SOLUTIONS  OF  KNOWN  CONTENT  OF  MANGANOUS  CHLORIDE  IN  DISTILLED  WATER  COM- 
PARED WITH  DILUTE  STANDARD  SOLUTION  OF  MANGANOUS  SULPHATE  TREATED 
IN    THE    SAME    MANNER    AND    DECANTED    INTO    NESSLER    TUBES. 


Cubic  centimeters  of  solution. 

Milligrams  of  manganese. 

Manganous 
chloride. 

Standard 
manganous 
sulphate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical value. 

0.0 

0.0 

0.00 

0.00 

+0.00 

.2 

.2 

.02 

.025 

—  .005 

.2 

.2 

.02 

.025 

—  .005 

.4 

.5 

.05 

.050 

-+-  .00 

.4 

6 

.06 

.050 

+   .01 

.6 

.7 

.07 

.075 

—  .005 

.6 

.8 

.08 

.075 

+   .005 

.8 

1.2 

.12 

.100 

-f-    .02 

.8 

1.0 

.10 

.100 

-4-  .00 

1.0 

1.2 

.12 

.125 

—  .005 

1.0 

1.0 

.10 

.125 

—  .025 

1.2 

1.4 

.14 

.150 

—  .01 

1.2 

1.7 

.17 

.150 

+   .02 

1.5 

2.0 

.20 

.187 

+   .013 

1.5 

2.2 

.22 

.187 

+    -033 

2.0 

2.5 

.25 

.250 

-f-   .00 

2.0 

2.0 

.20 

.250 

—  .05 

2.5 

3.5 

.35 

.312 

+   .038 

2.5 

3.0 

.30 

312 

—  .012 

3.0 

4.0 

.40 

.375 

+   .025 

3.0 

4.5 

.45 

.375 

-f   .075 

3.5 

5.0 

.50 

.438 

+   .062 

3.5 

4.5 

.45 

.438 

+   .012 

4.0 

5.0 

.50 

.500 

•+•  .000 

4.0 

6.0 

.60 

.500 

+   .100 

Mean    +   -012 

The  most  probable  source  of  error  in  the  determination  seemed 
to  be  in  filtering  through  asbestos,  as  a  very  small  amount  of  a  reduc- 
ing agent,  like  organic  matter  or  compounds  of  manganese  in  the 
filter  medium,  would  easily  affect  such  very  dilute  solutions  of 
permanganate.  In  order  to  eliminate  this  factor  the  determinations 
were  made  without  filtration.  Series  4  (Table  4)  was  made  with 
manganous  chloride  diluted  with  distilled  water.  The  comparisons 
were  made,  after  the  treated  solutions  had  been  decanted  into  Nessler 
tubes,  with  standard  solutions  of  manganous  sulfate  treated  in  all 
respects  like  the  samples.  Series  5  (Table  5)  was  like  series  4  except 
that  the  comparison  of  the  solutions  was  made  in  the  original  beak- 


LEAD-PEROXIDE  METHOD 


13 


ers  alter  allowing  the  lead  peroxide  to  settle.  Series  6  (Table  6)  was 
like  series  5  except  that  the  samples  were  prepared  by  adding  the 
solution  of  manganous  chloride  to  tap  water  instead  of  distilled 
water.  The  tap  water  is  a  bicarbonate  water  from  deep  wells ;  it  con- 
tains no  manganese  and  practically  no  chloride  or  sulphate;  it  has 
a  turbidity  of  5  parts,  a  color  of  15  parts,  due  to  its  content  of  iron 
and  organic  matter,  and  a  content  of  iron  of  2  parts  per  million.  The 
results  of  these  three  series  show  much  greater  accuracy  than  those  of 
the  first  three,  in  which  the  solutions  were  filtered  through  asbestos. 
In  series  4,  in  which  the  comparisons  were  made  after  the  supernatant 
liquid  had  been  decanted  into  Nessler  tubes,  difficulty  was  experi- 
enced on  account  of  incomplete  settling  of  the  lead  peroxide,  some 
was  invariably  decanted,  thus  causing  a  dark  color,  which  obscured 
the  color  to  be  compared.  In  series  5,  in  which  comparisons  were 
made  in  the  original  beakers,  this  difficulty  was  not  encountered.  The 
colors  can  not  be  matched  so  accurately  in  beakers,  however,  as  the 
relatively  shallow  depths  of  solution  make  the  differences  in  color 
appear  less  marked.  The  determinations  made  with  tap  water  in 

TABLE  5. — FIFTH  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 

THE  LEAD-PEROXIDE  METHOD. 

SOLUTIONS  OP  KNOWN  CONTENT  OF  MANGANOUS  CHLORIDE  IN  DISTILLED  WATER  COM- 
PARED WITH  DILUTE  STANDARD  SOLUTION  OP  MANGANOUS  SULPHATE  TREATED 
IN  THE   SAME  MANNER  IN  ORIGINAL  BEAKERS. 


Cubic  centimeters  of  solution. 

Milligrams  of  manganese. 

Manganous 
chloride. 

Standard 
manganous 
sulphate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical value. 

0.0 

0.00 

0.00 

0.00 

+0.00 

.2 

.2 

.02 

.025 

—  .005 

.2 

.2 

.02 

.025 

—  .005 

.4 

.5 

.05 

.050 

-+-  .00 

.4 

.4 

.04 

.050 

—  .01 

.6 

.7 

.07 

.075 

—  .005 

.6 

.6 

.06 

.075 

—  .015 

.8 

1.2 

.12 

.100 

+   .02 

.8 

1.0 

.10 

.100 

-+-  .00 

1.0 

1.4 

.14 

.125 

4-    .015 

1.0 

1.1 

.11 

.125 

—  .015 

1.2 

1.5 

.15 

.150 

•4-    .00 

1.2 

1.4 

.14 

.150 

—  .01 

1.5 

2.0 

.20 

.187 

+    .013 

1.5 

1.6 

.16 

.187 

—  .027 

2.0 

2.5 

.25 

.250 

•+-  .00 

2.0 

3.0 

.25 

.250 

•4-    .00 

2.5 

3.5 

.35 

.312 

+   .038 

2.5 

3.0 

.30 

.312 

—  .012 

3.0 

4.0 

.40 

.375 

+    .025 

3.0 

3.5 

.35 

.375 

—  .025 

3.5 

4.5 

.45 

.438 

+    .012 

3.5 

4.0 

.40 

.438 

—  .038 

4.0 

5.0 

.50 

.500 

•+-  .000 

4.0 

5.0 

.50 

.500 

±  .000 

—  .002 

14 


MANGANESE  IN  WATER  SUPPLIES 


series  6  are  as  accurate  as  those  with  distilled  water.  Manganese 
can,  therefore,  be  determined  with  a  fair  degree  of  accuracy  by  the 
lead-peroxide  method  in  waters  which  contain  little  chloride  and 
organic  matter.  A  content  as  small  as  0.02  milligram  can  be  detected 
in  a  volume  of  50  cubic  centimeters  by  comparison  of  colors  in  Ness- 
ler  tubes.  The  presence  of  organic  matter  in  large  amounts  causes 
error,  but  the  error  from  this  source  in  ordinary  samples  is  inappreci- 
able as  the  results  with  tap  water  show. 

The  presence  of  chloride,  which  has  a  reducing  action  on  per- 
manganate, also  causes  an  error.  In  order  to  determine  how  serious 
the  effect  due  to  chloride  might  be,  series  7  (Table  7)  wras  conducted, 
in  which  evaporation  with  sulphuric  acid  was  omitted  and  5  milli- 
grams of  chloride  as  sodium  chloride  was  added  to  tap  water.  Low 
results  were  generally  obtained.  The  average  deviation  from  the 
theoretical  values  is  .015  milligram.  When  10  and  25  milligrams  of 
chloride  were  present  no  test  whatever  for  manganese  could  be 
obtained.  It  is  essential,  therefore,  that  chloride  be  removed  for 
serious  errors  are  introduced  even  by  the  presence  of  small  amounts 

TABLE  6. — SIXTH  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 
THE  LEAD-PEROXIDE  METHOD. 

SOLUTIONS  OP  KNOWN  CONTENT  OF  MANGANOUS  CHLORIDE  IN  TAP  WATER  COMPARED 

WITH  DILUTE  STANDARD  SOLUTION  OF  MANGANOUS  SULPHATE  TREATED 

IN  THE  SAME  MANNER  IN  ORIGINAL  BEAKERS. 


Cubic  centimeters  of  solution. 

Milligrams    of    manganese. 

Manganous 
chloride. 

Standard 
manganous 
sulphate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical value. 

0.0 

0.0 

0.00 

0.00 

+0.00 

.2 

.2 

.02 

.025 

—  .005 

.2 

.2 

.02 

.025 

—  .005 

.4 

.5 

.05 

.050 

-+•  .00 

.4 

.5 

.06 

.050 

+   .01 

.6 

.7 

.07 

.075 

—  .005 

.6 

.8 

,08 

.075 

+   .005 

.8 

1.0 

.10 

.100 

-+-  .00 

.8 

1.0 

.10 

.100 

•+•  .00 

1.0 

1.2 

.12 

.125 

—  .005 

1.0 

1.4 

.14 

.125 

+   .015 

1.2 

1.5 

.15 

.150 

•4-  .00 

1.2 

1.7 

.17 

.150 

+   .02 

1.5 

2.0 

.20 

.187 

+   -013 

1.5 

1.7 

.17 

.187 

—  .017 

2.0 

2.0 

.20 

.250 

—  .05 

2.0 

2.3 

.23 

.250 

—  .02 

2.5 

3.0 

.30 

.312 

—  .012 

2.5 

3.5 

.35 

.312 

+    .038 

3.0 

3.5 

.35 

.375 

—  .025 

3.0 

4.0 

.40 

.375 

+    .025 

3.5 

4.0 

.40 

.438 

—  .038 

3.5 

4.0 

.40 

.438 

—  .038 

4.0 

5.0 

.50 

.500 

-f-  .000 

4.0 

5.0 

.50 

.500 

±  .000 

Mean    

—  .004 

SODIUM-BISMUTHATE  METHOD 


15 


of  that  radicle.      Chloride  is  present  in  many  natural  waters  in 
amounts  greater  than  those  used  in  these  experiments. 

THE  SODIUM-BISMUTHATE  METHOD 

Schneider1  appears  to  have  been  the  first  to  use  bismuth  perox- 
ide for  the  oxidation  of  manganous  salts  to  permanganate.  Other 
workers  found,  however,  that  the  presence  of  chloride  in  this  oxide 
was  deleterious,  and  to  overcome  this  trouble  Reddrop  and  Ramage2 
substituted  sodium  bismuthate,  which  could  be  more  easily  obtained 
free  from  chloride.  The  bismuthate  method  has  been  used  widely 
in  analysis  of  iron  and  steel  and  has  been  shown  to  be  accurate.  It 
is  described  by  Dufty,3  Blair,4  Blum,5  Hillebrand  and  Blum,6  and 
others.  Weston7  first  advocated  it  for  use  in  water  analysis  in  1907, 


TABLE  7. — SEVENTH  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 
THE  LEAD-PEROXIDE  METHOD. 

SOLUTIONS  OF  KNOWN  CONTENT  OF  MANGANOUS  CHLORIDE  IN  TAP  WATER  COMPARED 

WITH  DILUTE  STANDARD  SOLUTION  OF  MANGANOUS  SULPHATE  IN  THE 

PRESENCE  OF  5  MILLIGRAMS  OF  CHLORIDE. 


Cubic  centimeters  of  solution. 

Milligrams    of    manganese. 

Manganous 
chloride. 

Standard 
manganous 
sulphate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical value. 

0.0 

0.0 

0.00                             0.00 

+0.00 

.2 

2 

.02 

.025 

—  .005 

.2 

'.2 

.02 

.025 

—  .005 

.4 

.3 

.03 

.050 

—  .02 

.4 

.4 

.03 

.050 

—  .02 

.6 

.5 

.05 

.075 

—  .025 

.6 

.6 

.06 

.075 

—  .015 

.8 

.7 

.07 

.100 

—  .03 

.8 

.9 

.09 

.100 

—  .01 

1.0 

1.1 

.11 

.125 

—  .015 

1.0 

1.2 

.12 

.125 

—  .005 

1.2 

1.2 

.12 

.150 

—  .03 

1.2 

1.4 

.14 

.150 

—  .01 

1.5 

1.8 

.18 

.187 

—  .007 

1.5 

2.0 

.20 

.187 

+    .013 

2.0 

2.5 

.25 

.250 

-4-  .000 

2.0 

2.0 

.20 

.250 

—  .05 

2.5 

3.0 

.30 

.312 

—  .012 

2.5 

3.0 

.30 

.312 

—  .012 

3.0 

3.5 

.35 

.375 

—  .025 

3.0 

3.5 

.35 

.375 

—  .025 

Mean  

...     —  .015 

1Schneider,  L.,  Methode  zur  Bestimmung  von  Mangan:  Dingl.  poly.  J.  269,  224   (1888). 

2Reddrop,  Joseph,  and  Ramage,  Hugh,  Volumetric  estimation  of  manganese:  J.  Chem. 
Soc.,  67,  268-77  (1895). 

3Dufty,  Lawrence,  Volumetric  estimation  of  manganese:    Chem.  News,   84,  248   (1901). 

4Blair,  A.  A.,  The  bismuthate  method  for  the  determination  of  manganese:  J.  Am.  Chem. 
Soc.,  26,  793-801  (1904). 

5Blurn,  William,  Determination  of  manganese  as  sulphate  and  by  the  sodium-bismuthate 
method:  Orig.  Com.  8th  Intern.  Congr.  Appl.  Chem.,  1,  61-85  (1912). 

'Hillebrand,  W.  F.,  and  Blum,  William,  The  determination  of  manganese  by  the  sodium- 
bismuthate  method:  J.  Ind.  Eng.  Chem.,  3,  374-6  (1911). 

7Weston,  R.  S.f  The  determination  of  manganese  in  water:  J.  Am.  Chem.  Soc.,  29, 
1074-8  (1907). 


16 


MANGANESE  IN  WATER  SUPPLIES 


before  which  year  manganese  in  water  was  seldom  determined.  He 
describes  the  method,  giving  some  data  which  show  it  to  be  sufficient- 
ly accurate.  The  procedure  for  this  method  recommended  by  the 
committee  on  standard  methods  of  water  analysis1  in  the  edition  pub- 
lished in  1912  is  based  on  Weston's  work. 

The  procedure  used  in  this  investigation  is  essentially  as  fol- 
lows. Different  amounts  of  the  standard  solution  of  manganous 
chloride  were  diluted  with  distilled  water  and  with  tap  water.  Each 
portion  was  then  evaporated  with  one  or  two  drops  of  sulphuric  acid 
(1  to  3)  until  white  fumes  appeared.  Distilled  water,  dilute  nitric 
acid,  and  0.5  gram  of  sodium  bismuthate  were  then  added,  after  which 
the  solution  was  heated  until  the  pink  color  disappeared.  After  it  had 
cooled  somewhat  an  excess  of  sodium  bismuthate  was  added,  the  solu- 
tion was  thoroughly  stirred,  then  filtered  through  an  asbestos  mat  in  a 
Gooch  crucible,  which  had  been  washed,  ignited,  and  treated  with 
potassium  permanganate.  The  solution  was  then  transferred  to  a 
Nessler  tube  and  compared  with  two  sets  of  standards,  one  prepared 

TABLE  8. — FIRST  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 
THE  BISMUTHATE  METHOD. 

SOLUTIONS  OF  KNOWN  CONTENT  OF  MANGANOUS  CHLORIDE  IN  DISTILLED  WATER 
COMPARED  WITH  DILUTE  STANDARD  SOLUTION  OF  POTASSIUM  PERMANGANATE. 


Cubic  centimeters  of  solution. 

Milligrams    of    manganese. 

Manganous 
chloride. 

Standard 
permanganate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical content. 

0.0 

0.0 

0.00 

0.00 

-f-0.00 

.2 

.2 

.02 

.025 

—  .005 

.2 

.2 

.02 

.025 

—  .005 

.4 

.4 

.04 

.050 

—  .01 

.4 

.5 

.05 

.050 

•+•  .00 

.6 

.7 

.07 

.075 

—  .005 

.6 

.7 

.07 

.075 

—  .005 

.8 

1.0 

.10 

.100 

-f-  .00 

.8 

1.0 

.10 

.100 

-+-  .00 

1.0 

1.2 

.12 

.125 

—  .005 

.0 

1.2 

.12 

.125 

—  .005 

.2 

1.5 

.15 

.150 

-t-  .00 

.2 

1.4 

.14 

.150 

—  .01 

.5 

2.0 

.20 

.    .187 

+    .013 

.5 

1.7 

.17 

.187 

—  .017 

2.0 

2.5 

.25 

.250 

•+•  .00 

2.0 

2.2 

.22 

.250 

—  .03 

2.5 

3.0 

.30 

.312 

—  .012 

2.5 

3.2 

.32 

.312 

+    .008 

3.0 

3.5 

.35 

.375 

—  .025 

3.0 

4.0 

.40 

.375 

+    .025 

3.5 

4.5 

.45 

.438 

+    .012 

3.5 

4.5 

.45 

.438 

+   .012 

4.0 

5.0 

.50 

.500 

-f-  .000 

4.0 

5.0 

.50 

.500 

-4-   .000 

Mean  —  .003 

1Standard  methods  for  the  examination  of  water  and  sewage,   Am.  Pub.  Health  Assoc., 
New  York,  2nd  ed.,  49-51  (1912). 


SODIUM-BISMUTHATE  METHOD 


17 


by  diluting  standard  potassium  permanganate  and  the  other  by  treat- 
ing  standard  solutions  of  manganous  sulphate  like  the  samples.  The 
results  obtained  are  shown  in  Tables  8  and  9.  A  third  series  (Table 
10)  was  run  in  the  same  manner  except  that  tap  water  was  used  in- 
stead of  distilled  water.  Filtration  through  asbestos  does  not  seem 
to  have  any  appreciable  reducing  effect  on  the  permanganate  when 
sodium  bismuthate  is  used  as  the  oxidizing  agent.  This  seems  strange 
for  when  lead  peroxide  was  used  the  effect  was  so  great  as  to  cause 
uniformly  low  values.  The  results  indicate  that  the  bismuthate 
method  is  accurate  under  all  the  conditions  here  observed.  A  content 
of  0.01  milligram  of  manganese  in  a  volume  of  50  cubic  centimeters 
can  be  detected  by  comparison  in  Nessler  tubes. 

In  order  to  determine  how  seriously  the  results  are  affected  by 
the  presence  of  chloride  5,  10,  and  25  milligrams  of  chloride  as 
sodium  chloride  were  added  to  different  portions,  and  evaporation 
with  sulfuric  acid  was  omitted.  The  determinations  made  under 
these  conditions  are  shown  in  Table  11.  The  results  indicate  that 
chloride  has  no  appreciable  effect  in  amounts  of  5  milligrams  or  less. 

TABLE  9. — SECOND  SERIES  OF  DETERMINATIONS  OP  MANGANESE  BU 
THE  BISMUTHATE  METHOD. 

SOLUTIONS  OF  KNOWN  CONTENT  OF  MANGANOUS  CHLORIDE  IN  DISTILLED  WATER 

COMPARED  WITH  DILUTE  STANDARD  SOLUTION  OF  MANGANOUS 

SULPHATE  TREATED  IN  THE  SAME  MANNER. 


Cubic  centimeters  of  solution. 

Milligrams    of   manganese. 

Manganous 
chloride. 

Standard 
manganous 
sulphate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical content. 

0.0 

0.0 

0.00 

0.00 

±0.00 

.2 

.2 

.02 

.025 

—  .005 

.2 

.2 

.02 

.025 

—  .005 

.4 

.4 

.04 

.050 

.01 

.4 

.5 

.05 

.050 

-t-  .00 

.6 

.7 

.07 

.075 

—  .005 

.6 

.8 

.08 

.075 

+   .005 

.8 

1.0 

.10 

.100 

±  .00 

.8 

1.0 

.10 

.100. 

•+•  .00 

1.0 

1.2 

.12 

.125 

—  .005 

1.0 

1.1 

.11 

.125 

—  .015 

1.2 

1.5 

.15 

.150 

-f-  .00 

1.2 

1.4 

.14 

'.150 

—  .01 

1.5 

2.0 

.20 

.187 

+   .013 

1.5 

2.0 

.20 

.187 

4-   .013 

2.0 

2.5 

.25 

.250 

•+•  .00 

2.0 

2.5 

.28 

.250 

+    .03 

2.5 

3.0 

.30 

.312 

—  .012 

2.5 

3.5 

.35 

.312 

-f   .038 

3.0 

3.5 

.35 

.375 

—  .025 

3.0 

4.0 

.40 

.375 

4-   .025 

3.5 

4.5 

.45 

.438 

-f    .012 

3.5 

4.0 

.4a 

.438 

—  .038 

4.0 

5.0 

.50 

.500 

•+•  .000 

4.0 

5.0 

.50 

.500 

±  .000 

Mean   +   .0002 

18 


MANGANESE  IN  WATER  SUPPLIES 


When  10  milligrams  or  more  of  chloride  are  present  the  results  are 
low.  The  effect  of  chloride  in  the  bismuthate  method  is  much  less 
pronounced  than  in  the  peroxide  method,  in  which  the  presence  of 
more  than  10  milligrams  of  chloride  wholly  prevented  the  appearance 
of  the  color  of  permanganate. 

The  bismuthate  method  is  decidedly  superior  to  the  lead-peroxide 
method.  The  color  of  the  permanganate  is  not  appreciably  weakened 
by  filtration  through  asbestos.  Comparison  of  colors  may,  therefore,  be 
made  by  filtering  and  transferring  to  Nessler  tubes.  The  presence  of 
chloride  does  not  interfere  so  seriously  in  the  bismuthate  as  in  the 
lead-peroxide  method.  That  the  permanganate  is  not  so  easily  re- 
ducible in  the  presence  of  sodium  bismuthate  as  in  the  presence  of 
lead  peroxide  is  probably  due  to  the  fact  that  the  bismuthate  is  a 
more  active  oxidizing  agent  than  the  peroxide.  The  results  were  as 
accurate  when  the  colors  were  compared  with  those  of  dilute  standard 
solutions  of  potassium  permanganate  as  when  compared  with  those 
of  solutions  of  manganous  sulphate  treated  like  the  samples.  The 

TABLE  10. — THIRD  SERIES  OF  DETERMINATIONS  OP  MANGANESE  B\ 
THE  BISMUTHATE  METHOD. 

SOLUTIONS  OP  KNOWN  CONTENT  OF  MANGANOUS  CHLORIDE  IN  TAP  WATER  COMPARED 

WITH  DILUTE  STANDARD  SOLUTION  OP  MANGANOUS  SULPHATE 

TREATED  IN  THE  SAME  MANNER. 


Cubic  centimeters  of  solution. 


Milligrams    of    manganese. 


Manganous 
chloride. 

Standard 
manganous 
sulphate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical content. 

0.0 

0.0 

0.00 

0.00 

+0.00 

.2 

.2 

.02 

.025 

—  .005 

.2 

.3 

.03 

.025 

+   .005 

.4 

.5 

.05 

.050 

-f-  .00 

.4 

.5 

.05 

.050 

-+-  .00 

.6 

.8 

.08 

.075 

+    .005 

.6 

.7 

.07 

.075 

—  .005 

.8 

.10 

.10 

.100 

-4-  .00 

.8 

.08 

.08 

.100 

—  .02 

1.0 

.12 

.12 

.125 

—  .005 

1.0 

.11 

.11 

.125 

+    .015 

1.2 

.15 

.15 

.150 

•+-   .00 

1.2 

.15 

.15 

.150 

-t-  .00 

1.5 

2.0 

.20 

.187 

4-    .013 

1.5 

1.8 

.18 

.187 

—  .007 

2.0 

2.5 

.25 

.250 

-+•  .00 

2.0 

2.2 

.22 

.250 

—  .03 

2.5 

3.0 

.30 

.312 

—  .012 

2.5 

3.5 

.35 

.312 

+   .038 

3.0 

4.0 

.40 

.375 

+   .025 

3.0 

4.0 

.40 

.375 

+   .025 

3.5 

4.5 

.45 

.438 

4-    .012 

3.5 

4.0 

.40 

.438 

—  .038 

4.0 

5.0 

.50 

.500 

-+-   .000 

4.0 

5.0 

.50 

.500 

±  .000 

Mean    

+   .001 

PERSULPHATE  METHOD 


19 


use  of  sodium  bismuthate  permits  detection  of    a    slightly    smaller 
amount  of  manganese  than  the  use  of  lead  peroxide. 

THE  PERSULPHATE  METHOD 

The  fact  that  persulphate  oxidizes  manganous  salts  to  perman- 
ganate in  the  presence  of  silver  nitrate  was  discovered  by  Marshall1, 
who  suggested  the  reaction  as  a  qualitative  test  for  manganese. 
Walters2  first  used  a  modified  form  of  the  method  for  the  quantita- 
tive determination  of  manganese  in  iron  and  steel.  After  the  man- 
ganese had  been  oxidized  to  permanganate  the  amount  was  found  by 
titrating  with  arsenious  acid.  This  method  is  now  widely  used  in 
metallurgical  work. 

In  water  analysis  comparison  of  the  colors  of  the  solutions  of 
permanganate  is  usually  made  instead  of  a  titration.  The  persulphate 


TABLE  11. — FOURTH  SERIES  OF  DETERMINATIONS  OP  MANGANESE  BY 
THE  BISMUTHATE  METHOD. 

SOLUTIONS  OF  KNOWN  CONTENT  OP  MANGANOUS  CHLORIDE  IN  DISTILLED  WATER 
CONTAINING  CHLORIDE  COMPARED  WITH  DILUTE  STANDARD 

SOLUTION  OF  POTASSIUM   PERMANGANATE. 
[Results  expressed  in  milligrams  of  manganese.] 


Solution  of 
manganous 
chloride. 

Theoretical 
content. 

Determined  content  of  manganese  in  presence  of 
designated  amounts  of  chloride. 

5  mg.          |        10  mg. 

25  mg. 

50  mg. 

Cubic    centimeters 

0.0 

0.000 

0.00 

0.00 

0.00 

0.00 

.2 

.025 

.02 

.02 

.00 

.00 

.2 

.025 

.03 

.02 

.00 

.00 

.4 

.050 

.05 

.04 

.03 

.00 

.4 

.  *      .050 

.05 

.03 

.02 

.00 

.6 

.075 

.08 

.07 

.05 

.03 

.6 

.075 

.07 

.08 

.06 

.04 

.8 

.100 

.10 

.09 

.08 

.05 

.8 

.100 

.10 

.10 

.07 

.05 

1.0 

.125 

.12 

.12 

.10 

.08 

1.0 

.125 

.14 

.12 

.08 

.10 

1.2 

.150 

.15 

.14 

.14 

.12 

1.2 

.150 

.15 

.13 

.12 

.10 

1.5 

.187 

.20 

.17 

.15 

.12 

1.5 

.187 

.20 

.15 

.15 

.15 

2.0 

.250 

.25 

.20 

.20 

.12 

2.0 

.250 

.30 

.25 

.20 

.20 

2.5 

.312 

.30 

.30 

.25 

.25 

2.5 

.312 

.28 

.32 

.28 

.20 

3.0 

.375 

.35 

.32 

.30 

.30 

8.0 

.375 

.40 

.32 

.32 

.25 

8.5 

.433 

.45 

.40 

.40 

.20 

3.5 

.438 

.45 

.35 

.30 

.20 

4.0 

.504 

.50 

.45 

.37 

.25 

4.0 

.504 

.40 

.45 

.40 

.20 

Marshall,  Hugh,  The  detection  and  estimation  of  minute  quantites  of  manganese:  Chem. 
News,  83,  76  (1901). 

^Walters,  H.  E.,  Ammonium  persulphate  as  a  substitute  for  lead  peroxide  in  the  colori- 
metric  estimation  of  manganese:  Chem.  News,  84,  239-40  (1901). 


20 


MANGANESE  IN  WATER  SUPPLIES 


method  has  been  advocated  by  Liihrig  and  Becker,1  Kodenburg,2 
Haas,3  Schowalter,4  Hartwig  and  Schellbach,5  and  Tillmans  and 
Mildner6,  but  most  of  these  authors  present  no  data  as  to  the  accu- 
racy of  the  method. 

In  the  writer's  work  with  the  ammonium-persulphate  method 
different  amounts  of  the  standard  solution  of  manganous  chloride 
were  diluted  with  distilled  water  or  with  tap  water  to  about  50  cubic 
centimeters  each.  Two  cubic  centimeters  of  nitric  acid  (1  to  1)  and 
.5  cubic  centimeters  of  2.0  per  cent  solution  of  silver  nitrate  were 
added.  After  the  mixture  had  been  boiled  and  shaken  it  was  filtered. 
About  0.5  gram  of  crystals  of  ammonium  persulphate  was  added  to 
the  filtrate,  and  the  solution  was  heated  gently  on  the  hot  plate  until 
the  maximum  color  of  permanganate  had  developed  after  which  it 
was  transferred  to  a  50  cubic  centimeter  Nessler  tube.  The  color  was 
compared  with  those  of  standards  prepared  by  diluting  with  water  a 
standard  solution  of  potassium  permanganate  or  by  treating  diluted 
amounts  of  a  standard  solution  of  manganous  sulphate  with  nitric 
acid,  silver  nitrate,  and  ammonium  persulphate  like  the  sample.  The 


TABLE  12. — FIRST  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 

THE  PERSULPHATE  METHOD. 

SOLUTIONS  OP  KNOWN  CONTENT  OP  MANGANOUS  CHLORIDE  IN  DISTILLED  WATER 
COMPARED  WITH  DILUTE  STANDARD  SOLUTION  OF  POTASSIUM  PERMANGANATE. 


Cubic  centimeters  of  solution. 

Milligrams    of    manganese. 

Manganous 
chloride. 

Standard 
permanganate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical content. 

0.0 

0.0 

0.00 

0.00 

-f-0.00 

.2 

.2 

.02 

.025 

—  .005 

.2 

.3 

.03 

.025 

+    .005 

.4 

.4 

.04 

.050 

—  .01 

.4 

.5 

.05 

.050 

•4-   .00 

.6 

.7 

.07 

.075 

—  .005 

.6 

.7 

.07 

.075 

—  .005 

.8 

1.0 

.10 

.100 

-4-    .00 

.8 

1.1 

.11 

.100 

-f    .01 

1.0 

1.2 

.12 

.125 

—  .005 

1.0 

1.0 

.10 

.125 

—  .025 

Mean  —  .003 

Liihrig,  H.,  and  Becker,  W.,  Zur  Bestimmung  des  Mangans  im  Trinkwasser:  Pharm. 
Zentralhalle,  48,  137-42  (1907). 

2Rodenburg,  J.,  Over  mangaanbepaling  in  leidingwater :  Chem.  Weekblad,  7,  877-9 
(1910). 

8Haas,  Fritz,  Ueber  die  colorimetrische  Bestimmung  kleiner  Mengen  von  Mangan  im 
Trinkwasser:  Z.  Nahr.  Genussm.,  25,  392-5  (1913). 

4Schowalter,  E.,  Colorimetrische  Bestimmung  kleiner  Mengen  von  Mangan  im  Trink- 
wasser: Z.  Nahr.  Genussm.,  26,  104-8  (1913);  also  Studien  zur  Kenntnis  des  Verlaufs  der 
Marshall' schen  Manganreaktion :  27,  553-62  (1914). 

BHartwig,  L.,  and  Schellbach,  H.,  Colorimetrische  Bestimmung  von  kleinen  Mengen  Man- 
gan in  Trinkwasser:  Z.  Nahr.  Genussm.,  26,  439-42  (1913). 

"Tillmans,  J.,  and  Mildner,  H.,  Mangan  im  Wasser,  sein  Nachweis  und  seine  Bestimmung : 
J.  Gasbel.,  67,  496-501,  523-6,  544-7  (1914). 


PERSULPHATE  METHOD 


21 


results  obtained  by  comparison  of  colors  according  to  these  methods 
are  given  in  Tables  12,  13,  14,  and  15. 

In  the  comparisons  with  standard  solution  of  potassium  perman- 
ganate diluted  with  water  (Table  12)  amounts  of  manganese  greater 
than  0.125  milligram  could  not  be  compared  easily  on  account  of  the 
difference  in  shade  between  the  standards  of  permanganate  and  the 
samples.  The  solutions  of  potassium  permanganate  were  reddish 
purple  while  the  samples  were  bluish  purple.  This  difference  in  hue 
was  noticeable  in  all  the  concentrations  used,  but  it  did  not  cause 
great  trouble  except  when  the  manganese  is  present  in  amounts  great- 
er than  0.10  or  0.12  milligram.  With  lower  concentrations  accurate 
results  were  obtained,  but  with  higher  concentrations  the  comparison 
was  too  unsatisfactory  to  be  used. 

When  the  standards  were  prepared  by  treating  diluted  solutions 
of  manganous  sulphate  in  the  same  manner  as  the  samples,  no  diffi- 
culty was  experienced  in  making  the  comparisons,  and  the  results 
(Tables  13  and  14)  show  that  the  method  is  accurate.  Series  3  in 
which  the  solution  of  manganous  chloride  was  diluted  with  tap  water 

TABLE  13. — SECOND  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 

THE  PERSULPHATE  METHOD. 

SOLUTIONS  OF  KNOWN  CONTENT  OF  MANGANOUS  CHLORIDE  IN  DISTILLED  WATER 
COMPARED  WITH  DILUTE  STANDARD  SOLUTION  OF  MANQANOUS  SUL- 
PHATE TREATED  IN  THE  SAME  MANNER. 


Cubic  centimeters  of  solution. 

Milligrams    of    manganese. 

Manganous 
chloride. 

Standard 
manganous 
sulphate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical content. 

0.0 

0.0 

0.00 

0.00 

+0.00 

.2 

.2 

.02 

.025 

—  .005 

.2 

.25 

.025 

.025 

-l-  .00 

.4 

.6 

.06 

.050 

+   .01 

.4 

.5 

.05 

.050 

-1-  .00 

.6 

.7 

.07 

.075 

—  .005 

.6 

.8 

.08 

.075 

+    .005 

.8 

1.0 

.10 

.100 

-+-  .00 

.8 

1.1 

.11 

.100 

-f    .01 

1.0 

1.2 

.12 

.125 

—  .005 

1.0 

1.2 

.12 

.125 

—  .005 

1.2 

1.4 

.14 

.150 

—  .01 

1.2 

1.4 

.16 

.150 

+    .01 

1.5 

1.8 

.18 

.187 

—  .007 

1.5 

1.8 

.18 

.187 

—  .007 

2.0 

2.4 

.24 

.250 

—  .01 

2.0 

2.5 

.25 

.250 

-+-  .00 

2.5 

3.0 

.30 

.312 

—  .012 

2.5 

3.3 

.33 

.312 

-f    .018 

3.0 

3.5 

.35 

.375 

—  .025 

3.0 

3.8 

.38 

.375 

+    .005 

3.5 

4,0 

.40 

.438 

—  .038 

3.5 

4.5 

.45 

.438 

-f    .012 

4.0 

5.0 

.50 

.500 

H-  .000 

4.0 

4.5 

.45 

.500 
Mean  . 

—  .050 

—  .004 

22 


MANGANESE  IN  WATER  SUPPLIES 


gave  as  accurate  results  as  those  in  which  distilled  water  was  used, 
the  mean  differences  for  the  two  series  of  twenty-five  determinations 
each  being,  respectively, — 0.003  milligram  and — 0.004  milligram.  The 
results  show  the  desirability  of  using  standards  which  have  been 
oxidized  with  persulphate  and  treated  in  all  respects  like  the  samples. 
A  content  of  0.005  milligram  of  manganese  in  a  volume  of  50  cubic 
centimeters  was  easily  detected  under  the  conditions  of  the  test. 

Liihrig1  states  that  a  high  content  of  chloride  interferes  in  the 
persulphate  method  by  causing  a  blue  coloration,  and  that  iron  inter- 
feres by  causing  a  reddish  coloration.  Yet  accurate  results  were  ob- 
tained by  the  writer  in  a  series  of  determinations  in  which  50,  100, 
and  200  milligrams  of  chloride  as  sodium  chloride  were  present.  ( See 
Table  15.)  No  bluish  coloration  was  noted,  and  no  difficulty 
was  experienced  in  matching  the  colors.  A  large  excess  of  silver 
nitrate  and  ammonium  persulphate  should  be  avoided  as  it  seems  to 
produce  a  cloudiness  perhaps  by  precipitate  of  silver  peroxide.  Mar- 

TABLE  14. — THIRD  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 
THE  PERSULPHATE  METHOD. 

SOLUTIONS  OP  KNOWN  CONTENT  OP  MANGANOUS  CHLORIDE  IN  TAP  WATER  COMPARED 

WITH  DILUTE  STANDARD  SOLUTION  OP  MANGANOUS  SULPHATE 

TREATED  IN  THE  SAME  MANNER. 


Cubic  centimeters  of  solution. 

Milligrams  of  manganese. 

Manganous 
chloride. 

Standard 

manganous 
sulphate. 

Determined 
content. 

Theoretical 
content. 

Excess  of  deter- 
mined over  theo- 
retical content. 

0.0 

0.0 

0.00 

0.00 

+0.00 

.2 

.3 

.03 

.025 

+    -005 

.2 

.2 

.02 

.025 

—  .005 

.4 

.5 

.05 

.050 

-t-  .00 

.4 

.5 

.05 

.050 

-t-  .00 

.6 

.7 

.07 

.075 

—  .005 

.6 

.7 

.07 

.075 

—  .005 

.8 

.9 

.09 

.100 

—  .010 

.8 

1.0 

.10 

.100 

-f-  .000 

1.0 

1.2 

.12 

.125 

—  .005 

1.0 

1.1 

.11 

.125 

—  .015 

1.2 

1.4 

.14 

.150 

—  .01 

1.2 

1.5 

.15 

.150 

-4-    .00 

1.5 

1.8 

.18 

.187 

—  .007 

1.5 

1.9 

.19 

.187 

+    .003 

2.0 

2.5 

.25 

.250 

•+-  .00 

2.0 

2.4 

.24 

.250 

—  .01 

2.5 

3.2 

.32 

.312 

+    .008 

2.5 

3.3 

.33 

.312 

+   .018 

3.0 

3.5 

.35 

.375 

—  .025 

3.0 

3.8 

.38 

.375 

+   .005 

3.5 

4.5 

.45 

.438 

+    .012 

3.5 

4.5 

.45 

.438 

-I-    .012 

4.0 

5.0 

.50 

.500 

•+•  .000 

4.0 

4.7 

.47 

.500 

—  .030 

Mean    —  .003 

aLuhrig,  H.,  Die  colorimetrische  Bestimmung  kleiner  Manganmengen  im  Wasser: 
Ztg.,  38,  781-3   (1914). 


Chem. 


COMPARISON  OF  METHODS 


23 


shall1  prepared  silver  peroxide  by  this  method,  and  the  interference 
noted  by  Liihrig  is  probably  caused  thus.  Large  amounts  of  iron 
doubtless  interfere  on  account  of  the  yellow  color  of  ferric  salts.  When 
manganese  is  present  the  mixture  produces  the  reddish  coloration 
noted  by  Liihrig. 

COMPARISON   OF  THREE   COLORIMETRIC   METHODS 

In  order  to  compare  the  three  colorimetric  methods  for  deter- 
mination of  manganese  under  working  conditions,  the  manganese  in 
several  natural  waters  was  determined  by  each  method.  The  amounts 
found,  together  with  the  amounts  of  residue,  chloride,  iron,  and  the 
alkalinity  to  show  the  character  of  the  waters,  are  given  in  Table  16. 
The  samples  were  taken  below  Streator  from  Vermilion  River,  which 
is  polluted  by  coal-mine  drainage,  and  their  contents  of  iron  and  chlo- 
ride are  large.  In  the  persulphate  method  chloride  was  precipi- 
tated by  silver  nitrate,  added  in  slight  excess,  and  was  removed  by 
filtration.  The  colorimetric  comparison  was  made  with  standard 

TABLE  15. — FOURTH  SERIES  OF  DETERMINATIONS  OF  MANGANESE  BY 
THE  PERSULPHATE  METHOD. 

SOLUTIONS  OF  KNOWN  CONTENT  OF  MANGANOUS  CHLORIDE  IN  TAP  WATER  CONTAINING 
CHLORIDE  COMPARED  WITH  STANDARD  SOLUTION  OF  MANGANOUS  SUL- 
PHATE TREATED  IN  THE  SAME  MANNER. 

[Results  expressed  in  milligrams  of  manganese.] 


Solution  of 
manganous 
chloride. 

Theoretical 
content. 

Determined  content  of  manganese  in  presence  of 
designated  amounts  of  chloride. 

50  mg. 

100  mg. 

200  mg. 

Cubic  centimeters. 

0.0 

0.000 

0.000 

0.000 

0.000 

.2 

.025 

.02 

.02 

.02 

.2 

.025 

.02 

.02 

.02 

.4 

.050 

.04 

.05 

.04 

.4 

.050 

.05 

.05 

.05 

.6 

.075 

.07 

.07 

.08 

.6 

.075 

.08 

.07 

.08 

.8 

.100 

.11 

.09 

.10 

.8 

.100 

.10 

.10 

.10 

1.0 

.125 

.12 

.13 

.12 

1.0 

.125 

.12 

.12 

.12 

1.2 

.150 

.14 

.15 

.16 

1.2 

.150 

.16 

.16 

.15 

1.5 

.180 

.18 

.19 

.17 

1.5 

.180 

.20 

.20 

.19 

2.0 

.250 

.22 

.      .22 

.25 

2.0 

.250 

.25 

.24 

.25 

2.5 

.312 

.30 

.30 

.32 

2.5 

.312 

.28 

.30 

.30 

3.0 

.375 

.35 

.35 

.40 

3.0 

.375 

.40 

.35 

.40 

3.5 

.438 

.45 

.40 

.45 

3.5 

.438 

.45 

.45 

.50 

4.0 

.504 

.50 

.45 

.55 

4.0 

.504              1               .50 

.50 

.50 

1Marshall,  Hugh,  The  action  of  silver  salts  on  solution  of  ammonium  persulphate:  Proc. 
Royal  Soc.  Edinburgh,  23,  163-8   (1900). 


24 


MANGANESE  IN  WATER  SUPPLIES 


solution  of  manganous  sulphate  treated  in  the  same  manner  as  the 
sample.  In  the  bismuthate  method  evaporation  of  the  sample  with 
sulphuric  acid  was  omitted,  and  the  colorimetric  comparison  was 
made  with  standards  prepared  by  diluting  the  standard  solution  of 
potassium  permanganate.  In  the  lead-peroxide  method  the  tests  were 
made  with  and  without  nitration  through  Gooch  crucibles  and  "with 
and  without  evaporation  with  sulphuric  acid,  and  standards  were  pre- 
pared by  treating  portions  of  the  dilute  solution  of  manganous  sul- 
fate  in  the  same  manner  as  the  samples.  The  amounts  determined 
by  the  persulphate  and  the  bismuthate  methods  agree  very  well.  The 
amounts  found  by  the  lead-peroxide  method  with  chloride  removed 
and  without  filtering  through  Gooch  crucibles  also  agree  very  well 
with  those  obtained  in  the  persulphate  and  the  bismuthate  methods. 
The  results  were  low,  however,  when  chloride  was  not  first  removed 
and  irregular  results  were  obtained  when  the  Gooch  crucible  was 
used  for  filtration. 

TABLE  16. — DETERMINATIONS  OF  MANGANESE  IN  NATURAL  WATERS 

BY  COLORIMETRIC  METHODS. 

[Parts  per  million.] 


Manganese   (Mn). 

Lead-peroxide  method. 

Total 
residue. 

Chloride 
(01). 

Alkalinity 
as  Ca  CO3. 

Iron 
(Fe). 

Persul- 
phate 
method. 

Bismu- 
thate 
method. 

Gooch  crucible. 

Decantation. 

Chlo- 

Chlo- 

Chlo- 

Chlo- 

rine 

rine 

rine 

rine 

not  re- 

re- 

not re- 

re- 

moved. 

moved. 

moved. 

moved. 

848 

42 

460 

0.4 

0.25 

0.15 

0.0 

0.0 

0.2 

0.2 

2328 

60 

20 

150. 

4.5 

4.0 

3.0 

3.0 

4.0 

5.0 

2070 

80 

20 

86. 

4.0 

3.2 

2.0 

4.8 

3.0 

4.0 

2290 

83 

26 

90. 

4.0 

4.2 

2.5 

3.2 

3.0 

4.0 

2198 

84 

40 

65. 

5.5 

5.0 

3.0 

5.0 

5.0 

5.0 

2371 

103 

60 

66. 

7.5 

7.0 

6.0 

7.0 

7.0 

8.0 

2293 

103 

122 

4.0 

8.0 

9.5 

4.0 

6.0 

6.0 

8.0 

345 

25 

144 

.2 

.0 

.0 

.0 

.0 

2396 

102 

90 

46.5 

9.0 

8.5 

6.0 

7'.  6 

8.0 

7'.  6 

1591 

17 

92 

126.5 

1.4 

1.4 

0.6 

1.6 

1.0 

1.5 

2660 

65 

200 

57.5 

2.0 

1.8 

1.8 

2.0 

2.0 

2.0 

1970 

92 

4 

48.0 

4.0 

4.0 

2.0 

6.0 

3.0 

4.0 

RELATIVE  VALUE  OF  COLORIMETRIC  METHODS 

The  persulphate  method  is  the  most  convenient  and  accurate 
method  for  the  colorimetric  determination  of  manganese  in  water. 
Chloride,  being  necessarily  removed  by  precipitation,  does  not  inter- 
fere. As  small  amount  as  0.005  milligram  of  manganese  in  a  volume 
of  50  cubic  centimeters,  equivalent  to  0.1  part  per  million,  can  be  de- 
tected. The  bismuthate  method  recommended  by  the  committee  on 


OCCURRENCE  25 

standard  methods  of  water  analysis1  is  accurate  and  reliable.  The 
presence  of  chloride  in  amounts  less  than  5  milligrams  does  not  in- 
terfere with  this  determination,  and  evaporation  with  sulphuric  acid 
may  be  omitted  unless  the  water  contains  much  organic  matter.  By 
this  method  0.01  milligram  of  manganese  in  a  volume  of  50  cubic 
centimeters,  equivalent  to  0.2  part  per  million,  can  be  detected.  The 
lead-peroxide  method  accepted  by  the  committee  on  standard 
methods  of  water  analysis  gives  results  which  are  seriously  low  be- 
cause of  reduction  of  permanganate  in  using  the  Gooch  crucible.  If 
this  step  is  omitted  more  nearly  accurate  results  are  obtained.  The 
presence  of  chloride  interferes  in  this  method  more  seriously  than  in 
either  of  the  others,  and  if  more  than  5  milligrams  of  chloride  are 
present  no  manganese  may  be  found  even  if  a  comparatively  large 
amount  is  present;  evaporation  with  sulphuric  acid  is,  therefore, 
necessary.  About  0.02  milligram  of  manganese  in  a  volume  of  50 
cubic  centimeters,  equivalent  to  0.4  part  per  million,  can  be  detected 
by  the  decantation  method.  The  peroxide  method  is  at  best  the  least 
sensitive  of  the  three,  and  it  should  be  rejected  as  a  standard 
method. 

It  seems  advisable  to  adopt  as  standard: 

(1)  The  persulphate  method,  in  which    colorless    nitric    acid 
should  be  used,  evaporation  with  sulphuric  acid  should  be  omitted 
unless  large  amounts  of  organic  matter  are  present,  and  comparison 
should  be  made  with  standards  prepared  by  treating    solutions    of 
manganous  sulphate  exactly  like  the  sample  ; 

(2)  The  bismuthate  method,  in    which    colorless    nitric    acid 
should  be  used,  evaporation  with  sulphuric  acid  should  be  omitted 
unless  more  than  5  milligrams  of  chloride  or  much  organic  matter  is 
present,  and  comparison  should  be  made  with  standards  prepared  by 
treating  standard  solutions  of  manganous  sulphate  exactly  like  the 
sample   or  by  diluting  a  freshly  prepared   solution   of   potassium 
permanganate. 

MANGANESE  IN  WATER  SUPPLIES 
General  occurrence 

The  presence  of  manganese  in  water  supplies  in  concentrations 
great  enough  to  be  significant  has  always  been  considered  rather  un- 
usual, particularly  in  the  United  States.  Manganese  has  been  en- 
countered in  several  water  supplies  in  Europe. 


Standard  methods  for  the  examination  of  water  and  sewage,   Am.  Pub.  Health  Assoc., 
New  York,  2nd  ed.,  49-51   (1912). 


26  MANGANESE  IN  WATER  SUPPLIES 

R.  S.  Weston1  cites  some  twenty  ground-water  supplies  in  this 
country  and  in  Europe  which  have  been  reported  to  contain  man- 
ganese. 

TABLE  17. — MANGANESE  IN  CERTAIN  MUNICIPAL  WATER  SUPPLIES. 

Parts  per  million. 

Arad,    Hungary   Present 

Babylon,  N.  Y 07 

Bayshore,  N.  Y 37 

Berlin,    Germany  Present 

Bjornstorp,  Sweden 3.4     —  53.4 

Brunswick,  Germany  Present 

Breslau,  Germany Trace —    110 

Calverton,  N.  Y 30 

Halle,    Germany 1.50 

Hamburg,  Hofbriinnen 45 

Hanover,    Germany   Present 

Patchogue,  N.  Y 20 

Beading,  Mass 004 —     .56 

Stargard,  Germany   Present 

Stettin,  Germany 5.22 

Superior,    Wisconsin   12 

Shewsbury,    Mass 10 

The  first  water  in  this  country  in  which  manganese  was  reported 
in  sufficient  quantity  to  cause  trouble  was,  from  a  well  supplying  a 
New  England  mill  in  1898.  This  supply  was  abandoned  because  of 
its  high  content  of  manganese.  Sixty-two  springs  in  the  United  States 
are  listed  by  Mason2  as  having  been  reported  to  contain  manganese. 
He  states  that  nearly  half  of  them  contain  only  traces  of  the  element 
and  that  only  seven  contain  as  much  as  the  4.5  parts  per  million 
which  he  found  in  a  mineral  spring  at  Excelsior  Springs,  Mo. 
Kaumer3  reports  a  water  near  Fiirth  which  contained  6.2  parts  per 
million  of  manganese.  Bailey4  states  that  the  well-water  supply  of 
Hutchinson,  Kans.,  contains  1.0  part  per  million  of  manganese. 

1Weston,  E.  S.,  The  purification  of  ground  waters  containing  iron  and  manganese :  Trans. 
Am.  Soc.  0.  E.,  64,  112-81  (1909). 

^ason,  W.  P.,  The  manganese  waters  of  Excelsior  Springs:  Chem.  News,  61,  123  (1890). 

8Raumer,  E.  von,  Ueber  das  Auftreten  von  Eisen  und  Mangan  in  Wasserleitungswasser : 
Z.  anal.  Chem.,  42,  590-602  (1903). 

*Bailey,  E.  H.  S.,  Occurrence  of  manganese  in  a  deposit  found  in  city  water  pipes: 
J.  Am.  Chem.  Soc.,  26,  714-5  (1904). 


OCCURRENCE  27 

The  trouble  in  Breslau1  in  1906  is  a  classic  example  of  injury  to 
a  water  supply  by  very  high  contents  of  iron  and  manganese. 
Breslau  was  formerly  supplied  with  water  from  Oder  River,  but  in 
1905  a  supply  was  substituted  from  313  driven  wells  30  to  40  feet 
deep  in  Oder  valley.  In  March,  1906,  the  Oder  overflowed  its  banks, 
and  soon  afterward  the  turbidity,  odor,  hardness,  residue,  manganese, 
and  iron  in  the  ground- water  supply  enormously  increased.  The  con- 
tent of  iron  increased  to  440  and  the  content  of  manganese  to  220 
parts  per  million.  The  filtered  water  from  Oder  River  was  necessarily 
substituted  for  the  ground- water  supply.  Many  explanations  have 
been  offered  for  this  peculiar  change  in  the  quality  of  the  water. 
Most  authorities  agree  that  it  was  caused  by  a  process  of  oxidation  and 
leaching  of  the  soil,  which  contains  a  large  amount  of  sulfides  of  iron 
and  manganese.  The  iron  sulfide  was  oxidized  to  iron  sulfate  by  the 
dissolved  oxygen  of  the  river  water.  The  water  containing  iron  sul- 
phate then  percolated  through  the  soil  to  the  water-bearing  strata,  a 
part  hydrolyzing  to  sulphuric  acid  which  dissolved  the  manganese. 
Extensive  experiments  on  the  removal  of  iron  and  manganese  from  the 
supply  have  been  carried  on  by  a  number  of  investigators. 

Manganese  waters  at  Bjornstorp  Estate,  Sweden,  are  described 
by  Weibull.2  Pipes  were  clogged,  and  fabrics  laundered  in  several 
waters  from  ponds  and  wells  in  the  vicinity  were  turned  yellow.  In- 
vestigation showed  that  some  of  the  waters  contained  as  much  as  6.3 
parts  per  million  of  manganous  oxide,  or  5  parts  per  million  of  man- 
ganese which  was  precipitated  upon  exposure  to  the  air.  The  rock 
formation  in  the  vicinity  is  gneiss  and  diorite,  the  latter  of  which 
contains  8.2  per  cent  of  manganous  oxide,  which  probably  accounts 
for  the  high  content  of  manganese  of  the  waters. 

A  study  of  the  content  of  manganese  of  waters  in  France  has 
been  made  by  Jadin  and  Astrug.3  In  several  city  supplies  0.0005 
to  0.015  part  per  million  of  manganese  was  found.  Mineral  waters 
at  Vichy  and  Boulon  contained  0.09  to  0.20  part  per  million.  The 
content  of  manganese  of  sources  very  near  each  other  widely  differed. 

1Woy,  Rudolph,  Stoning  der  Breslauer  Wasserversorgung  durch  Mangansulf at :  Z. 
offent.  Chem.  12.  121-125  (1906)  ;  Kritische  Besprechung  der  Erfahrungen  mit  JLer  Breslauer 
Grundwasserversorgung :  13,  401-411  (1907). 

Liihrig,  H.,  t)ber  die  Ursachen  der  Breslauer  Grundwasserverschlechterung  und  die 
Mittel  zu  ihrer  Behelung:  Z.  Nahr.  Genussm.,  14,  40-63  (1907). 

Beyschlag,  F.,  and  Michael  R.,  Uber  die  Grundwasserverhaltnisse  der  Stadt  Breslau:  Z. 
prakt.  Geol.,  15,  153-64  (1907). 

Luhrig,  H.  and  Blasky,  A.,  Mangan  in  Grundwasser  der  Breslauer  Wasserleitung  und 
die  Frage  der  Abscheidung  des  Mangansulf ates  aus  demselben:  Chem.  Ztg.,  31,  255-7  (1907). 

Weston,  R.  S.,  The  purification  of  ground  waters  containing  iron  and  manganese:  Trans. 
Am.  Soc.  0.  E.,  64,  112-81  (1909). 

2Weibull,  Mats,  Ein  manganhaltiges  Wasser  und  eine  Bildung  von  Braunstein  bei 
Bjornstorp  in  Sweden.  Z.  Nahr.  Genussm.,  14,  403-5  (1907). 

8Jadin,  F.,  and  Astrug,  A.,  Le  manganese  dans  les  eaux  d'  alimentation  et  lea  eaux 
minerals:  Compt.  Rend.,  157,  338-9  (1913). 


28  MANGANESE  IN  WATER  SUPPLIES 

Discovery  of  manganese  in  several  city  water  supplies  of  Illi- 
nois prompted  an  investigation  to  determine  what  relations,  if  any, 
exist  between  geological  formation  and  content  of  manganese  and  to 
determine  the  source  of  the  manganese  in  the  supplies.  Accordingly, 
manganese,  iron,  and  dissolved  solids  were  determined  in  a  large 
number  of  samples  from  representative  sources  throughout  the  State. 
Samples  were  taken  from  streams  and  from  wells,  concerning  which 
reliable  information  was  available  concerning  the  geological  strata 
penetrated.  As  complete  information  of  this  kind  concerning  many 
private  wells  is  not  available  whereas  rather  complete  logs  are  usually 
kept  of  city  wells  most  of  the  supplies  examined  are  city  water  sup- 
plies. The  samples  were  taken  at  the  original  sources,  preliminary 
work  having  shown  that  manganese  may  completely  separate  in  the 
pipes  before  the  water  reaches  distant  taps. 

Methods  of  Analysis 
MANGANESE 

The  colorimetric  persulfate  method  was  used  for  the  determina- 
tion of  manganese.  Two  hundred  and  fifty  cubic  centimeters  of  the 
sample  were  acidified  with  2  cubic  centimeters  of  nitric  acid  (1  to  1) 
and  concentrated  to  a  volume  of  less  than  50  cubic  centimeters.  If  the 
sample  contained  more  than  0.20  milligram  of  manganese  a  smaller 
amount  was  used  for  the  determination.  Surface  waters  and  in  general 
waters  showing  a  clayey  or  silica-like  turbidity  were  filtered  before 
making  the  determination.  After  concentration  chloride  was  pre- 
cipitated with  a  solution  of  silver  nitrate  added  in  slight  excess,  and 
the  precipitate  was  removed  by  filtration.  Samples  which  were  very 
high  in  chloride  were  evaporated  with  sulphuric  acid  until  white 
fumes  were  evolved,  after  which  distilled  water  and  a  small  amount 
of  the  solution  of  silver  nitrate  were  added.  One-half  gram  of  crystals 
of  ammonium  persulphate  was  then  added,  and  the  solution  was 
warmed  until  the  maximum  color  of  permanganate  had  developed. 
Standards  were  prepared  containing  0.2,  0.4,  0.6,  and  more  cubic  centi- 
meters of  standard  solution  of  manganous  sulphate,  which  was  diluted 
to  similar  volume  and  treated  in  exactly  the  same  manner  as  the  sample 
was  treated.  The  sample  and  the  standards  were  then  transferred  to 
50-cubic  centimeter  Nessler  tubes  and  the  colors  were  compared. 
If  the  above  procedure  is  followed  the  limit  of  detection  is  0.02  part 
per  million. 


OCCURRENCE  29 

IRON 

Iron  was  determined  either  colorimetrically  with  potassium  sul- 
phocyanide  or  by  titration  with  permanganate  after  the  weighed 
oxides  of  iron  and  aluminium  had  been  fused  and  dissolved. 

DISSOLVED  SOLIDS 

Dissolved  solids  is  the  residue  obtained  by  evaporating  to  dryness 
100  cubic  centimeters  of  the  sample,  heating  the  residue  at  180  °C.  for 
one  hour,  and  weighing  it.  Samples  having  a  clayey  or  silica-like  tur- 
bidity were  filtered  before  evaporation.  If  the  turbidity  was  due  to 
precipitated  ferric  hydroxide  the  sample  was  not  filtered. 

Manganese  in  Waters  of  Illinois 

The  supplies  have  been  grouped  as  follows  with  reference  to 
source : 

1.  Wells  in  Potsdam  sandstone. 

2.  Wells  in  St.  Peter  sandstone. 

3.  Wells  in  limestone. 

4.  Wells  in  unconsolidated  deposits. 

5.  Springs. 

6.  Coal-mine  drainage. 

7.  Lakes  and  streams. 

WELLS  IN  POTSDAM  SANDSTONE 

Seventeen  supplies  from  wells  entering  Potsdam  sandstone  were 
examined.  (See  Table  18.)  No  manganese  could  be  detected  in  four- 
teen of  them.  A  small  amount  was  found  in  three,  0.08  part  per  mil- 
lion in  water  from  a  well  at  Chicago,  and  0.04  part  in  water  from  wells 
at  Riverside  and  Utica.  These  amounts  are  so  small  as  to  be  of  little 
significance.  The  content  of  iron  ranges  from  0.0  to  3.6  parts  per  mil- 
lion and  dissolved  solids  from  278  to  5,520  parts.  No  relation  is  ap- 
parent between  the  contents  of  manganese,  iron,  and  total  mineral 
matter.  Manganese  apparently  is  not  present  in  most  water  from 
wells  drawing  chiefly  from  Potsdam  sandstone  in  Illinois. 

WELLS  IN  ST.  PETER  SANDSTONE 

Twenty-eight  samples  from  wells  entering  St.  Peter  sandstone 
were  examined.  (See  Table  18.)  Manganese  was  absent  from  all  but 
two  of  them.  One  of  these  was  from  a  1,300-foot  well  at  Elgin,  which 
furnished  a  water  containing  0.10  part  per  million.  As  this  well  is 


30 


MANGANESE  IN  WATER  SUPPLIES 


TABLE  17. — CONTENT  OF  MANGANESE,  IRON,  AND  DISSOLVED  SOLIDS 

IN  WATER  FROM  WELLS  ENTERING  POTSDAM  SANDSTONE. 

[Parts  per  million.] 


Locality. 

County. 

Depth. 

Manganese 
(Mn). 

Iron 
(Fe). 

Dissolved 
solids. 

Aledo 

Feet. 
3  165 

0  00 

0  0 

2  078 

Lee 

2  400 

00 

1  4 

450 

Kane 

2  000 

00 

4 

2  198 

L'elvidere  
Biiie  Island  

Boone  
Cook  

1,800 
2  000 

.00 
00 

.0 
2 

511 
1  246 

Byroii  .-  
Carbon  Hill 

Ogle  

2,000 
1  800 

.00 
00 

.0 

g 

288 
1  295 

Chicago8  
Chicago*  

Cook  
do   

2,100 
1  600 

.08 
00 

3.6 

4 

5,520 
1  057 

Dixona  

Lee  

1  922 

00 

1 

301 

940 

00 

2 

278 

Forest  Park  
Minonk 

Cook  

Woodford 

2,015 
1  765 

.00 

oo 

.0 
2 

530 
2  337 

Morrison 

"Wh'teside 

2  048 

00 

5 

293 

Riverside  

Cook 

2  000 

04 

2 

891 

Utica  

La  Salle 

350 

04 

5 

444 

Waukegan  

Lake  

1,300 

.00 

.1 

557 

•Not  public  supply. 

TABLE  18. — CONTENT  OF  MANGANESE,  IRON,  AND  DISSOLVED  SOLIDS 
IN  WATER  FROM  WELLS  ENTERING  ST.  PETER  SANDSTONE. 

[Parts  per  million.] 


Locality. 

County. 

Depth. 

Manganese 
(Mn). 

Iron 
(Fe). 

Dissolved 
solids. 

Abingdon  
Bellwood  
Chad  wick 

Knox  
Cook  
Carroll 

Feet. 
1,350 
1,400 
fiflO 

0.00 
.00 
on 

0.0 
1.0 

1,323 
546 

Chenoa        .             . 

2  100 

00 

i  1 

1   98Q 

Cuba  *  .  .  .  . 

Fulton 

1  765 

00 

2*4.Q 

Elgin  
Do    

Kane  
do   

1,300 
1  300 

.10 
00 

3.2 

377 
493 

Peoria 

•I    «Jf)A 

oo 

Fulton 

1  465 

00 

Galesburg  
Genoa  . 

Knox  
DeKalb 

1,240 
1  500 

.00 
00 

.0 

1,515 

Henry  

Marshall 

1  355 

00 

Ipava  

Fulton 

1  575 

00 

2Q77 

Jerseyville  

Jersey  . 

1  542 

00 

300-1 

1  485 

00 

Lena  . 

600 

00 

4.Q7 

Oregon  
Park   Ridge  
Peru 

Ogle  
Cook  

La    Salle 

1,600 
1,425 
1  500 

.00 
.00 
00 

.8 
1.0 

285 
820 

River  Forest  
Rochelle  
Roseville    . 

Cook  
Ogle  

Warren 

1,000 
1,026 
1  260 

.03 
.00 
00 

.1 
.1 

452 
337 

Kfifi 

Rockdale*  
Spring  Valley.  .  .  ,  .    . 

Will  
Bureau  

657 
1  400 

.00 
00 

1.4 
.4 
1 

2,596 
527 
770 

Sycamore  .                 . 

Dekalb 

905 

00 

0    O 

•lAf) 

Toulon  

Stark 

1  465 

00 

o 

11  4.7 

Warren  

Jo  Daviess 

865 

00 

j 

070 

Wyoming  

Stark  

1,557 

.00 

Trace 

1,047 

•Not  city  supply. 

cased  only  100  feet  and  the  pumps  were  started  for  the  purpose  of 
taking  the  sample,  water  from  some  upper  stratum  also  may  have 
entered  the  well.  The  other  water,  from  a  1,000-foot  well  at  River 
Forest  contained  very  little  manganese.  The  content  of  iron  of  these 


OCCURRENCE 


31 


supplies  ranged  from  0.0  to  4.0  parts  per  million,  and  dissolved  solids 
from  285  to  2,977  parts.  Manganese,  then,  is  evidently  absent  from 
most  waters  in  St.  Peter  sandstone  in  Illinois,  and  no  relation  appears 
to  exist  between  the  contents  of  manganese,  iron,  and  dissolved  min- 
eral matter. 

WELLS  IN  LIMESTONE 

Tests  of  samples  from  27  wells  entering  limestone  are  given  in 
Table  19.  Manganese  was  found  in  water  from  wells  at  Flora, 
Marion,  Matteson,  and  San  Jose,  although  not  more  than  0.08  part 
per  million  is  found  in  any  of  the  waters  examined.  Such  small 
amounts  are  without  practical  significance.  The  content  of  iron  ranges 
from  0.0  to  4.8  parts  per  million  and  dissolved  solids  from  255  to 
3,395  parts.  Manganese,  then,  is  occasionally  found  in  small  amounts 
in  water  from  wells  drawing  chiefly  from  limestone,  but  it  is  usually 
absent. 


TABLE  19. — CONTENT  OF  MANGANESE,  IRON,  AND  DISSOLVED  SOLIDS 
IN  WATER  FROM  WELLS  ENTERING  LIMESTONE. 

[Parts  per  million.] 


Locality. 

County. 

Depth. 

Manganese 
(Mn). 

Iron 
(Fe). 

Dissolved 
solids. 

Union        .  .            .  .  . 

Feet. 
650 

0  00 

0  0 

347 

Harrington  
Carbondale      

Cook  
Jackson  

325 
410 

.00 
00 

.4 
1 

397 
2  igs 

Do            

do 

610 

00 

4 

3*395 

Fairfield    

Wayne  

200 

00 

4 

905 

Flora  

Clay  

240 

08 

o 

145 

Forreston  
Highland  Park8  
Lake  Forest* 

Ogle  
Lake  
do 

300 
395 
242 

.00 
.00 
00 

.0 
.0 
2 

610 
490 
''55 

Leland 

La    Salle 

230 

00 

4  8 

337 

Libertyville  

Manteno      .       .       .  ~ 

Lake  
Kankakee  

128 
60 

.00 
00 

I 
4 

712 
678 

Williamson  

700 

04 

3 

1  801 

Do 

do         

700 

00 

4 

1  110 

Do 

do         

700 

.04 

.2 

1  127 

Do 

do         

800 

.05 

.2 

1  562 

Do      

do         

960 

.06 

.3 

1  535 

Matteson  

Cook  
Grundy    

283 
650 

.04 
00 

4.0 

o 

713 
434 

Mount  Morris  
Pecatonica 

Ogle  

800 
500 
20 

.00 
.00 

.1 
.1 

500 
336 

105 

08 

o 

539 

Steger  

Will  

318 

.00 

1.0 

465 

Trenton 

Clinton                  .       . 

235 

00 

3 

980 

Villa  Grove 

Douglas    

629 

.00 

o 

591 

West  Chicago  
North  Crystal  Lake.  . 

Dupage  
McHenry  

322 
285 

.00 
.00 

.8 
.3 

405 
344 

'Not  city  supply. 


WELLS  IN  UNCONSOLIDATED  DEPOSITS 


Fifty-seven  waters  from  wells  in  unconsolidated   deposits   were 
examined.     (See  Table  20.)     The  unconsolidated  deposits  of  Illinois 


32 


MANGANESE  IN  WATER  SUPPLIES 


TABLE  20. — CONTENT  OF  MANGANESE,  IRON,  AND  DISSOLVED  SOLIDS 
IN  WATER  FROM  WELLS  IN  UNCONSOLIDATED  DEPOSITS. 

[Parts  per  million.] 


Locality. 

County. 

Depth. 

Manganese 
(Mn). 

Iron 
(Fe). 

Dissolved 
solids. 

Arlington  Heights.  .  . 

Cook  

Feet. 
125 

0  00 

0  2 

751 

Arthur  ... 

Moultrie 

7c 

00 

2  2 

4.Q1 

Bement  

Piatt  

141 

04 

1  5 

547 

Bloomington  

McLean 

100 

00 

1 

768 

Braidwood  

Will 

20 

08 

3 

492 

Camp  Point*  

Adams 

40 

12 

825 

Canton8  

Fulton      .       . 

10 

1  10 

g 

194 

Carlyle*  

25 

2  80 

26  0 

Champaign  

160 

00 

2  0 

389 

Chillicothe  

Peoria  

35 

00 

3 

504 

Crystal  Lake  

McHenry  

32 

00 

06 

444 

Danville*  .    . 

150 

00 

1  5 

431 

Do     *  

do 

150 

00 

4 

420 

Duquoin  

Perry    .  . 

30 

1  50 

2 

1  066 

Edwardsville*  

Madison.  .  . 

55     80 

5 

1  8 

252 

Eureka  

Woodford   .  .  . 

90 

08 

3  0 

509 

Freeport  

At) 

.20 

00 

ij 

719 
432 

Gibson  City  

Ford  

55 

04 

I 

320 

Grand  Ridge  

La  Salle  

196 

12 

8 

328 

Greenview  

Menard  

80 

50 

1  0 

655 

Havana  

Mason 

75 

08 

o 

202 

Henry  

Marshall 

40 

00 

o 

518 

Morgan 

30 

00 

1  7 

515 

Do        

do 

35 

00 

2  0 

424 

Do        

do      . 

35 

00 

1  8 

372 

Keithsburg  • 
Lacon  

Mercer  
Marshall 

35 

en 

.16 

no 

.3 

o 

1,262 
400 

LaHarpe  

Hancock  

43  —  63 

12 

10  0 

515 

LaRose*  

Marshall  

28 

12 

3  0 

500 

Lawrenceville*  

Lawrence  

30 

00 

.0 

424 

Do            

do 

15 

08 

1 

309 

Do 

do 

30 

00 

1 

273 

Do            

do 

11 

08 

2 

340 

Do            

do 

13 

00 

1 

279 

Do            

do 

20 

00 

1 

377 

Lexington  

McLean 

115 

00 

1.0 

400 

Lovington*  

Moultrie  . 

147 

08 

1.3 

548 

Mansfield  

Piatt  

214 

04 

2.1 

390 

Marengo        . 

McHenry 

14 

04 

1 

392 

Mount  Sterling11 

53 

28 

3 

698 

Neoga  

16 

00 

o 

299 

Pekin  

Tazewell 

80      128 

00 

.1 

465 

Peoria  

Peoria 

60 

16 

.0 

394 

Do     

do 

60 

44 

.0 

303 

Do     

do      

60 

1.60 

.1 

302 

Do 

do 

60 

75 

8 

270 

Do 

do 

60 

75 

6 

289 

Do 

do 

90 

08 

.0 

413 

Roanoke.  . 

Woodford 

30 

.06 

.9 

900 

Rushville.  .  .  . 

20 

.24 

.2 

362 

Sheffield  

50 

.20 

.1 

505 

Springfield  

Sangamon 

45 

.60 

2.0 

325 

Staunton  

Macoupin  

20 

.12 

.0 

325 

Tolono  

Champaign  

140 

.00 

1.8 

647 

Urban  a 

do 

160 

.00 

2.0 

380 

Washington 

Tazewell 

80  —  90 

.00 

2.4 

367 

Woodstock  

McHenry  

85 

.00 

2.6 

403 

•Not  city  supply. 


may  be  divided  mainly  into  two  classes;  glacial  drift  is  material  de- 
posited by  glaciers  in  their  movement  over  the  State;  alluvium  is 
material  deposited  by  rivers.  Carefully  recorded  records  of  the  strata 
penetrated  by  wells  are  necessary  in  order  to  determine  whether  wells 
near  large  rivers  are  in  glacial  drift  or  in  alluvium.  The  mineral  mat- 


OCCURRENCE 


83 


ter  in  water  from  wells  in  alluvium  may  not  represent  exclusively 
mineral  matter  extracted  from  alluvium,  for  part  or  all  of  the  water 
that  circulates  in  alluvium  may  have  entered  from  contiguous  beds  of 
glacial  material.  Few  wells  from  which  waters  were  examined  pene- 
trate alluvium  only,  and  available  data  regarding  several  wells  did 
not  permit  precise  classification  of  the  materials  as  glacial  drift  in 
distinction  from  alluvium.  All  the  wells  in  this  group  have,  there- 
fore, been  designated  wells  in  unconsolidated  deposits  with  distinc- 
tion between  alluvium  and  glacial  drift.  The  content  of  manganese 
of  these  57  waters  ranges  from  0.0  to  2.8  parts  per  million.  Twenty- 
two,  or  39  per  cent,  contain  more  than  0.10  part  per  million,  and  9, 
or  16  per  cent  contain  0.5  part  per  million  or  more.  The  results  ob- 
tained are  plotted  in  Figure  1.  Waters  from  unconsolidated  deposits 
in  the  eastern  part  of  the  State  contain  little  or  no  manganese,  those 
containing  the  large  amounts  are  in  the  western  part.  The  waters 
with  the  greatest  content  of  manganese  are  near  the  rivers ;  10  of  the 
13  waters  that  contain  more  than  0.2  part  per  million  of  manganese 
are  from  wells  in  flood  plains  or  terraces  of  rivers.  The  analyses  of 
the  17  waters  from  wells  in  flood  plains  or  terraces  have  been  grouped 
in  Table  21.  As  12  of  the  17  reveal  contents  of  more  than  0.2  part 
per  million  of  manganese  it  seems  that  wells  in  unconsolidated  deposits 
near  rivers  are  more  likely  to  contain  manganese  than  those  in  uncon- 
solidated deposits  elsewhere. 

TABLE  21. — CONTENT  OF  MANGANESE,  IRON,  AND  DISSOLVED  SOLIDS 
IN  WATER  FROM  WELLS  IN  UNCONSOLIDATED  DEPOSITS  NEAR  RIVERS. 

[Parts  per  million.] 


Locality. 

County. 

Depth. 

River. 

Manga- 
nese 
(Mn). 

Iron 
(Fe). 

Dis- 
solved 
solids. 

Carlyle  

Clinton  

Feet. 
25 

Kaskaskia 

2  8 

26  0 

Chilli  cothe    

Peoria  

35 

Illinois 

00 

3 

504 

Edwardsville.  .  .  . 

Madison  , 

55 

5 

1.8 

252 

Freeport  

80 
40 

Pecatonica        

28 

.7 

432 

75 

.08 

.0 

202 

Keithsburg  

35 

Mississippi    < 

.16 

.3 

1,262 

Lacon           

Marshall 

50 

Illinois 

00 

.0 

400 

Peoria  

Peoria            . 

60 

do 

16 

.0 

394 

Do     . 

do    .               ... 

60 

do 

.44 

.0 

303 

Do     ... 

do    

60 

do                         ... 

1.60 

.1 

302 

Do     

do    . 

60 

do                    

.75 

.8 

270 

Do     

do    

60 

do     

75 

.6 

289 

Do     

do    

90 

do      

08 

.0 

413 

Pulton  

10 

do     

1.10 

.6 

194 

Henry  

Marshall 

40 

do 

00 

o 

518 

Rushville  

Schuyler 

20 

do 

24 

2 

362 

Sangamon  

45 

.60 

2.0 

325 

34 


MANGANESE  IN  WATER  SUPPLIES 


Figure  1. — Map  of  Illinois  showing  occurrence  of  manganese  in  water  from 
wells  in  unconsolidated  deposits. 


OCCURRENCE 


35 


The  great  difference  in  content  of  manganese  of  water  from  five 
60-foot  wells  within  a  few  hundred  feet  of  one  another  at  Peoria  is 
rather  striking.  The  content  of  manganese  of  water  from  these  wells 
ranges  from  0.16  to  1.6  parts  per  million,  and  other  mineral 
constituents  also  present  similar  differences.  The  percentages  of 
manganese  are  shown  in  Table  22.  Though  no  data  concerning 
the  normal  content  of  manganese  of  unconsolidated  material  are  avail- 
able the  content  of  these  samples  does  not  seem  unusual,  but  it  may 
be  sufficiently  great  to  account  for  the  occurrence  of  manganese  in 
waters  circulating  in  the  deposits.  No  apparent  relation  exists  be- 
tween the  contents  of  manganese,  iron,  and  total  mineral  matter  of 
these  waters. 


TABLE  22. — MANGANESE  IN  BORINGS  FROM  TEST  WELLS  IN  UNCON- 
SOLIDATED DEPOSITS  AT  PEORIA. 


Number  of  well. 

Depth  of  sample. 

Content  of  manganese. 

Feet. 

Per  cent. 

2 

0  —  8.5 

0.21 

7 

3.5—18 

.30 

78 

0—  5 

.57 

78 

5—  8.5 

.46 

78 

8.5—19.5 

.56 

78 

19.4—24.2 

.31 

119 

0  —  5.5 

.46 

119      • 

5.5—  7.5 

,22 

119 

7.5—  9 

.23 

119 

21.6  —  coal 

.23 

TABLE  23. — CONTENT  OF  MANGANESE,  IRON,  AND  DISSOLVED  SOLIDS 
IN  WATER  FROM  SPRINGS.* 

[Parts  per  million.] 


Locality. 

County. 

Manganese 
(Mn). 

Iron 
(Fe). 

Dissolved 
residue. 

Ashland  

Cass  

0  00 

1  8 

490 

Adams  

40 

1  2 

876 

Harrisburg  
Jacksonville  

Saline  
Morgan 

.12 

00 

2.3 

o 

281 

378 

Kewanee  
Oregon  

Henry  
Ogle.  

.16 

00 

2.4 
5 

541 
402 

Do      

do    

00 

2 

449 

Jefferson  

7  80 

51  2 

1  189 

Clay  

.00 

3  4 

1  272 

Taylorville  

Morgan  

.00 

.0 

368 

•None  of  these  springs  is  used  as  a  public  water  supply. 

SPRINGS 

The  10  waters  from  springs  that  were  examined  show  wide 
range  in  content  of  manganese.  (See  Table  23.)  Six  samples  con- 
tained none,  3  contained  0.4  part  per  million  or  less,  and  one  contained 
7.8  parts  per  million.  The  water  from  Green  Lawn  Spring  at  Mount 
Vernon  has  a  greater  content  of  manganese  than  that  from  the  spring 


36 


MANGANESE  IN  WATER  SUPPLIES 


at  Excelsior  Springs,  Mo.,  which  contains  4.5  parts  per  million.1  The 
water  contains  no  bicarbonates  or  free  sulphuric  acid,  and  the  iron 
and  manganese  are  reported  as  sulphates. 

A  surf  ace  water  at  Mount  Vernon  (see  Table  25.)  also  contains 
0.12  to  0.80  part  per  million  of  manganese.  Water  from  a  well 
at  Camp  Point,  where  the  water  of  next  greatest  content  of  manga- 
nese is  situated,  contains  0.12  part  per  million  of  manganese.  (See 
Table  20.) 

TABLE  24. — CONTENT  OF  MANGANESE,  IRON,  AND  DISSOLVED  SOLIDS 
IN  WATER  FROM  COAL  MINES. 

[Parts  per  million.] 


Locality. 

County. 

Source. 

Manganese 
(Mn). 

Iron 

(Fe). 

Dissolved 
solids. 

Perry  

Abandoned  mine.  .  .  . 

0  24 

0  1 

1  160 

Danville  

Harrisburg  

Saline  

stripping  mine.  .  .  . 

17.0 
56  0 

5.0 

7  33Q 

Ladd 

1  3 

2  8 

3-1  A  A 

Streator.  . 

La  Salle  

do              .... 

1  4 

126  5 

1  379 

Do       

do       

Stobb's  mine  

2.0 

57.5 

2,245 

COAL-MINE  DRAINAGE 

Coal-mine  drainage  usually  contains  iron  and  often  large 
amounts  of  it,  and  such  drainage  is  often  acid  because  of  hydrolysis 
of  salts  of  iron  and  precipitation  of  iron  hydroxide.  The  iron 
is  derived  from  pyrite,  marcasite,  sulphide-bearing  shales,  and 
other  compounds  of  sulphur,  which  are  leached  by  water  containing 
oxygen,  and  oxidized  to  ferrous  sulphate,  a  compound  soluble  in 
water.  Though  manganese  has  not  been  considered  a  constituent  of 
mine  water  examination  of  6  samples  (See  Table  24)  of  coal-mine 
drainage  shows  that  all  contain  manganese  and  that  some  contain 
large  amounts.  The  content  of  manganese  of  one  sample,  which  con- 
tained free  acid  when  it  was  analyzed  was  56  parts  per  million.  All 
the  samples  of  mine  drainage  contained  large  amounts  of  dissolved 
mineral  matter,  but  none  except  that  from  Harrisburg  contained  free 
acid.  No  report  of  such  large  amounts  of  manganese  in  mine  water 
has  come  to  the  writer's  attention.  No  trace  of  manganese  could  be 
found  even  in  one-gram  samples  of  pyrite,  marcasite,  and  shale  from 
mines  in  the  Streator  district.  A  sulphide  shale,  which  occurs  with 
the  coal  in  the  stripping  mine  at  Danville,  where  water  containing 
17  parts  per  million  of  manganese  was  found,  sontained  1.10  per  cent 
of  manganese.  Manganese  probably  is  leached  from  minerals  by  mine 
drainage  in  a  manner  similar  to  the  removal  of  iron. 


iMason,   W.  P. 
(1890). 


The  manganese  waters  of  Excelsior   Springs:      Chem.   News,   61.   123 


OCCURRENCE 


37 


TABLE  25. — CONTENT  OF  MANGANESE,  IRON,  AND  DISSOLVED  SOLIDS 
IN  WATER  FROM  LAKES  AND  STREAMS. 

[Parts  per  million.] 


Locality. 

County. 

Source. 

Manganese 
(Mn). 

Iron 
(Fe). 

Dissolved 
solids. 

Reservoir  on, 

o 

6 

170 

Belleville  

St.  Glair  
Franklin  

Kohler  Creek  
Mississippi  River  .... 
Reservoir  on  creek.  .  .  . 

7.5 
0.02 
.12 

1.0 
0.1 
3.5 

214 
234 

282 

Cairo      

Alexander  

Ohio  River  

.00 

.1 

150 

Carlinville 

Macoupin  Creek  

00 

j 

240 
317 

Centralia 

Crooked  Creek  

20 

j_ 

Chicago  
Danville 

Cook  

Lake  Michigan  ...  •  •  • 

.00 
00 

.0 

151 

309 

Macon  

Sangamon  River 

.02 
on 

.1 

o 

454 
305 

East  St.  Louis  .  .  .  . 

St.   Glair  
Effingham 

Mississippi   River  
Little  Wabash  River  .  . 

.02 

.1 
.1 

1 

375 
230 
235 

Cook 

Lake  Michigan  

no 

o 

158 

Fort  Sheridan      .  . 

do 

do              

no 

o 

162 

do 

do 

155 

Granite  City 

Madison  

Mississippi  River.    .  .  . 

02 

1 

218 

Cumberland  .... 

Embarrass  River  

00 

05 

681 

Hamilton    

Hancock  

Mississippi  River  .... 

00 

o 

160 

Saline 

00 

.1 
3 

274 
671 

Highland  Park 

Lake 

Lake  Michigan  

oo 

05 

140 

oo 

1  6 

1,041 

Kankakee  River  

04 

1 

377 

La  Salle 

4  00 

150  0 

2,210 

Cook 

no 

Q 

192 

Lake 

do 

no 

Q 

177 

Lawrenceville      .  . 

Lawrence 

Embarrass  River.  .  .  . 

02 

1 

575 

Lowell*  

La  Salle  

Vermilion  River  

7  50 

66  0 

1.054 
2,316 

Madison  

Madison  

Mississippi  River  .... 

02 

.1 

224 

do                .... 

00 

1 

191 

Wabash 

Wabash  River  

00 

1 

300 

Mount  Vernon 

Reservoir  

12 

1 

215 

Do         

do       .    . 

.8 
00 

.8 
1 

402 
155 

North  Chicago.  .  . 

Lake   

Lake  Michigan  

00 

o 

164 

Oblong8  

Crawford  

Creek  

36 

1  0 

1,353 

Olney  

Richland  

Fox  River  

04 

.7 

145 

Oglesbya 

La  Salle 

9  00 

46  5 

2,325 

Pontiac 

do 

00 

05 

447 

Pullman  ,.  .  . 

Cook      .    . 

Lake  Michigan    

.08 
00 

.2 

o 

557 
151 

Quincy  

Adams  .      . 

Mississippi  River.  .  .  . 

00 

1 

222 

Rock  Island 

do 

.02 
02 

J 

1 

250 

224 

Stauuton        . 

Cahokia  Creek 

16 

1 

550 

Streator  

La    Salle 

00 

o 

848 

Venice  

02 

1 

234 

Waukegan  

Lake 

00 

o 

134 

West  Hammond  .  . 

Cook 

do 

00 

o 

146 

'Not  city  supply. 

. 


RIVERS  AND  LAKES 


No  manganese  was  found  in  any  of  the  waters  from  Lake  Michi- 
gan (See  Table  25),  and  not  more  than  0.02  part  was  found  in  any 
of  the  samples  from  Mississippi,  Ohio,  Wabash,  and  Sangamon  Rivers. 
Samples  from  Fox  and  Embarrass  Rivers  contained  only  small 
amounts.  The  water  of  Vermilion  River  below  Streator  contains  4 
to  9  parts  per  million  of  manganese,  and  much  larger  amounts  of  iron, 


38  MANGANESE  IN  WATER  SUPPLIES 

as  shown  by  analyses  of  samples  collected  at  Kangley,  Lowell,  and 
Oglesby.  Samples  taken  at  Streator  above  the  dam  at  the  water- 
works contained  no  manganese  or  iron.  This  river  below  Streator  is 
heavily  polluted  with  mine  drainage  containing  iron  and  manganese, 
a  condition  that  explains  the  high  content  of  manganese  and  iron.  The 
presence  of  0.32  part  per  million  of  manganese  in  the  city  supply  of 
Harrisburg  which  is  taken  from  Saline  River,  is  also  due. to  the  en- 
trance above  the  city  of  coal-mine  drainage  of  high  content  of  man- 
ganese. 

Many  impounding  reservoirs  on  small  creeks  in  southern  Illinois 
like  the  supplies  at  Anna,  Benton,  Centralia,  and  Mount  Vernon, 
contain  manganese.  Such  reservoirs  are  fed  partly  by  springs,  which 
may  contribute  the  manganese.  Their  content  of  manganese  widely 
varies.  At  Anna  a  variation  from  0.2  to  7.5  parts  per  million  from 
July,  1914  to  May,  1915,  was  observed,  and  at  Mount  Vernon  from 
0.1  to  0.8  part  per  million  during  the  same  period.  The  occurrence 
of  such  amounts  of  manganese  in  surface  waters  nearly  saturated 
with  dissolved  oxygen  is  contrary  to  past  conceptions  of  the  occur- 
rence of  the  element.  In  fact,  much  experimental  work  on  the  re- 
moval of  manganese  has  been  based  on  the  theory  that  aeration  oxi- 
dizes the  manganous  salt  to  an  insoluble  hydrated  oxide,  which  can  be 
removed  by  nitration. 

SUMMARY 

Manganese  as  a  constituent  of  water  supplies  in  the  United 
States  has  been  overlooked  and  its  importance  underestimated.  It  oc- 
curs normally  in  certain  classes  of  water  in  Illinois,  and  amounts  suf- 
ficient seriously  to  affect  the  quality  have  been  found  in  several 
waters.  This  may  be  said  of  the  water  supplies  at  Mount  Vernon, 
Anna,  Centralia,  Peoria,  Springfield,  Freeport,  and  Harrisburg. 

Little  manganese  is  present  in  water  from  Potsdam  sandstone, 
St.  Peter  sandstone,  the  overlying  limestones,  Lake  Michigan,  and  the 
large  rivers.  ^ 

Manganese  is  usually  present  and  often  in  very  large  amounts  in 
coal-mine  drainage. 

Manganese  is  present  in  water  from  some  impounding  reservoirs 
on  small  streams  in  southern  Illinois,  and  from  some  wells  entering 
unconsolidated  deposits  near  rivers. 

No  apparent  relation  exists  between  the  content  of  manganese 
of  a  water  and  any  of  the  other  mineral  constituents. 


METHODS  OF  REMOVAL  39 

REMOVAL  OF  MANGANESE  FKOM  WATER  SUPPLIES 
Methods 

The  experimental  work  which  has  been  done  on  the  removal  of 
manganese  from  water  has  led  to  the  development  of  three  practical 
methods — aeration  and  filtration  through  sand,  filtration  through 
permutit,  and  filtration  through  pyrolusite.  The  problem  of  remov- 
ing manganese  has  been  attacked  by  most  workers  in  a  manner  similar 
to  that  of  removing  iron.  The  usual  method  for  the  removal  of  iron 
from  water  is  by  aeration  followed  by  filtration  through  sand,  and  it 
is  generally  and  successfully  used  in  many  plants  in  the  United  States 
and  Europe.  Iron  occurs  in  most  ground  waters  in  the  ferrous  con- 
dition. When  the  water  is  aerated  the  iron  is  oxidized  to  the  ferric 
condition  and  separates  as  the  hydroxide.  This  combination  of  oxida- 
tion, hydrolysis,  and  precipitation  is  the  basic  principle  of  the  method 
though  the  presence  of  other  substances  somewhat  affects  the  results. 
The  occurrence  of  manganese  with  iron  in  many  waters  and  its  sep- 
aration as  the  hydrated  dioxide  under  certain  conditions  have  led  to 
the  assumption  that  the  element  in  water  has  chemical  properties 
practically  similar  to  those  of  iron. 

Extensive  experiments  on  removal  of  manganese  by  this  method 
have  been  conducted  by  Thiesing,1  who  worked  with  a  water  at  Pom- 
merensdorf,  Germany.  He  has  concluded  that  manganese  occurring 
in  water  as  the  bicarbonate  can  be  successfully  removed  by  aera- 
tion and  filtration.  Trickling  through  beds  of  coke  or  spraying  through 
nozzles  were  used  as  methods  of  aeration.  The  removal  of  carbon 
dioxide  as  well  as  solution  of  oxygen  was  found  to  be  important  in 
the  process  of  aeration.  Subsequent  filtration  through  sand  gave  an 
effluent  containing  very  little  manganese,  sedimentation  effected 
little  removal. 

In  this  country  extensive  experiments  along  similar  lines  have 
been  conducted  by  R.  S.  Weston2  with  several  waters  containing  iron 
and  manganese  in  Massachusetts.  Mr.  Weston 's  problems  have  dealt 
chiefly  with  the  removal  of  iron.  A  well  water  containing  0.73  part 
per  million  of  iron  and  0.23  part  per  million  of  manganese  was  treat- 
ed at  Cohasset  by  being  sprayed  through  nozzles  followed  by  passage 
through  a  coke  trickling  filter  and  mechanical  filters.  Satisfactory 
results  were  obtained  in  the  experiments  and  arrangements  have  been 
made  for  construction  of  a  large  plant.  In  experiments  at  Brookline 

Thiesing,  [Experiments  on  the  removal  of  manganese  from  ground  water] :  Mitt.  kgl. 
Prufungsans.  Wasserversorgung,  16,  210-96  (1912). 

^Weston,  R.  S.,  The  purification  of  ground  waters  containing  iron  and  manganese: 
Trans.  Am.  Soc.  C.  E.,  64,  112-81  (1909);  Some  recent  experiences  in  the  deferrization 
and  demanganization  of  water:  J.  N.  E.  Water  Works  Assoc.,  28,  27-59  (1914). 


40  MANGANESE  IN  WATER  SUPPLIES 

sprinkling  through  nozzles  followed  by  passage  through  a  coke  trick- 
ling filter  and  slow  sand  filters  decreased  the  content  of  iron  from  0.6 
to  0.2  part  per  million.  The  content  of  manganese  of  the  untreated 
water  was  0.26  part  per  million,  though  Weston  published  no  figures 
concerning  the  efficiency  of  the  removal  of  manganese  he  stated 
that  he  found  it  roughly  proportional  to  that  of  the  removal  of  iron. 
A  plant  for  removal  of  iron  and  manganese,  which  has  been  installed 
at  Middleboro,  treats  335,000  gallons  a  day  of  water.  The  water,  after 
it  has  been  sprayed  over  a  coke  trickling  filter  10  feet  deep,  flows 
into  a  settling  basin  and  through  slow  sand  filters  operating  at  a  rate 
of  10,000,000  gallons  per  acre  per  day.  The  content  of  iron  was  de- 
creased from  1.5  to  0.2  part  per  million  and  the  content  of  manganese 
from  0.67  to  0.27  part  per  million  during  the  first  run  from  Septem- 
ber 26,  1913,  to  January  12,  1914.  The  efficiency  of  the  removal  of 
manganese  increased  as  the  plant  was  operated  longer,  and  the  efflu- 
ent on  January  22  contained  0.10  part  per  million  of  manganese. 

Barbour1  performed  a  similar  series  of  experiments  on  the  well- 
water  supply  of  Lowell,  Mass.  The  waters  of  the  wells  differ  in  con- 
tent of  manganese,  the  strongest  containing  2.0  parts  per  million. 
Aeration,  sedimentation,  and  sand  filtration  were  tried  on  an  experi- 
mental scale.  The  efficiency  of  the  plant  was  at  first  rather  erratic, 
but  it  finally  became  possible  to  reduce  the  content  of  manganese  to 
0.01  part  per  million.  A  dark  coloration  due  to  precipitated  oxides 
of  manganese  was  observed  in  the  sand  bed,  and  this  extended  in 
diminishing  amounts  to  the  bottom  of  the  bed.  On  the  basis  of  this 
study  a  plant  was  erected  at  a  cost  of  $180,000  for  the  removal  of 
manganese  and  iron. 

Practically  all  students  of  removal  of  manganese  by  aeration  and 
filtration  have  concluded  that  manganese  is  much  more  difficult  to 
remove  than  iron.  The  details  of  the  process,  such  as  the  amount  of 
aeration  and  the  rate  of  filtration,  differ  with  the  character  of  the 
water. 

The  permutit  process  for  removal  of  manganese  has  come  recent- 
ly into  the  field.  Permutit,  the  artificial  zeolite2  first  produced  and 
patented  by  Gans  of  the  Prussian  Geological  Institute  of  Berlin,  has 
come  into  somewhat  common  use  in  softening  water.  Its  use  for  re- 
moving calcium  and  magnesium  from  water  has  been  studied  by 


1Barbour,  F.  A.,  Removal  of  carbonic  acid,  iron,  and  manganese  from  the  Lowell 
(Mass.)  well-water  supply:  Eng.  Record,  70,  78-9  (1914). 

2Gans,  Robert,  [Manufacture  of  artificial  zeolite  in  crystalline  form] :  U.  S.  pat. 
914,  405,  March  9,  1909,  Chem.  Rev.  Fett-Harz-Ind.,  16,  302-3  (1909). 

Duggan,  T.  R.,  Zeolites,  natural  and  artificial  (Abstract) :  Orig.  Com.  8th  Intern. 
Congr.  Appl.  Chem.  (Appendix),  25,  125-9  (1912). 

Gans,  Robert.  Ueber  die  technische  Bedeutung  der  Permutite  (der  kunstlichen 
zeolithartigen  Verbindungen)  :  Chem.  Ind.,  32,  197-200  (1909). 


METHODS  OF  REMOVAL  41 

numerous  investigators.  Gans,  however,  has  adapted  it  to  the  remov- 
al of  manganese  from  water.  The  principles  involved  in  this  latter 
process  are  decidedly  different  from  those  involved  in  ordinary  pro- 
cesses of  softening  water. 

Sodium  permutit  is  made  by  fusing  together  3  parts  of  kaolin,  6 
parts  of  sand,  and  12  parts  of  soda.  The  melt,  after  cooling,  is  leached 
with  water.  Gans1  proposes  the  following  to  represent  sodium  per- 
mutit. 

/  OH 
Si  —  OH          /  OH 

\0-A1 

\  0  —  :Na 
0 

/  OH 

Si  — OH 

\  OH 

The  sodium  in  this  compound  is  replaceable  by  other  metals.  For 
example,  when  a  solution  of  a  compound  of  calcium  percolates  through 
the  crushed  material,  the  calcium  replaces  the  sodium  in  the  silicate, 
is  removed  from  the  solution,  and  is  in  turn  replaced  in  the  water  by 
an  equivalent  of  sodium.  On  the  other  hand,  when  a  solution  of  a 
a  compound  of  sodium  is  filtered  through  the  calcium  permutit  the 
calcium  is  forced  out  by  the  sodium.  The  process  may  be  simply 
represented  by  the  equilibria : 

++  + 

Ca+2Na-permutit=2Na+  Ca-permutit. 

++  + 

Mg+2Na-permutit=2Na+Mg-permutit. 

Thus,  if  a  hard  water  percolates  through  sodium  permutit,  the 
calcium  and  magnesium  in  the  water  are  replaced  by  sodium.  If, 
after  this  change  is  complete,  a  solution  of  sodium  chloride  percolates 
through  the  used  permutit  the  calcium  and  magnesium  therein  are  re- 
placed and  removed  by  sodium.  The  permutit  is  thus  regenerated,  or 
restored,  to  its  original  condition  without  loss.  The  series  of  reactions 
constitutes  an  apt  application  of  the  law  of  mass  action.  Permutit 
is  not  lost  unless  the  water  contains  free  carbon  dioxide,  which  has 
on  the  permutit  a  solvent  action  that  results  in  the  formation  of 
bicarbonate. 

Gans2  noted  that  manganese  can  be  removed  with  compounds  of 

1Gans,  Robert.  Ueber  die  technische  Bedeutung  (der  Permutite  der  kiinstlichen  zeo- 
lithartigen  Verbindugen)  :  Chem.  Ind.,  32,  197-200  (1909). 

2Gans,  Robert,  Reinigung  des  Trinkwassers  von  Mangan  dutch  Aluminatsilicate:  Chem. 
Ztg.,  81.  355-6  (1907). 


42  MANGANESE  IN  WATER  SUPPLIES 

calcium  and  magnesium  when  a  manganese-bearing  water  is  filtered 
through  the  zeolite.  Usually,  however,  it  is  desired  to  remove  only 
the  manganese  without  the  extra  expense  of  softening  the  water.  To 
accomplish  this,  Gans1  treated  permutit  with  a  strong  solution  of 
manganous  chloride  or  sulphate,  and  then  with  a  strong  solution  of 
a  permanganate.  He  found  that  if  a  water  containing  manganese 
or  iron  is  filtered  through  this  medium,  the  manganese  and  iron  could 
be  removed  without  the  accompanying  softening  action.  After  a  time 
the  filter  medium  no  longer  effected  removal,  but  its  efficiency  was  re- 
stored by  regenerating  it  with  permanganate.  The  chemistry  of 
this  process  is  explained  by  Gans.1  Treatment  with  manganous  chlo- 
ride gives  a  manganese  zeolite. 

2SiO2  •  A12O3  •  CaO-f-MnCl2=  2SiO2  •  A12O3  •  MnO  -}-CaCl2 

When  this  zeolite  is  treated  with  permanganate,  the  following  re- 
actions may  take  place: 

(a)  2Si02-Al2(V  MnOa-f-CaMn2O8  2SiO2- Al2<VCaO-f-MnO -Mn2O7. 

(  2SKVAl30,-CaO  ) 

(b)  2(Si02-Al2O3-MnO)4-H2O+CaMn208—    j  2SiOa-AlaO,-  H2O  f  +2MnO-Mn2O7. 

2SiOa-Al2O,-CaO  j 

(c)  3(SiOa-Al2O,-MnO)-|-2H2O-fCaMn2O8=:  ^  2,SiO2- AlaO,-H2O  V+3MnO-MnaO7. 

2SiOa- AlaO,-H20  ) 


The  precipitation  of  manganese  by  these  zeolites,  which  depends 
on  the  action  of  the  oxides  of  manganese,  is  represented  by  the  follow- 
ing reactions: 

(a)  2(MnO-Mn2OT)+3Mn(HCO3)2=z5MnO-2Mn2O7-f-6CO2+3HaO 

(b)  2MnO  -Mn2O7+3Mn(HCO3)2=:5MnO  •  Mn2O7-f6CO2-f  3H2O 

(c)  2(3MnO-Mn2O7)-f  9Mn(HCO8)2—  ISMnO  •  2Mn2O7-f  18CO2-f  9H2O 

Gans2  successfully  applied  the  process  at  Glogau  to  a  water  that 
contained  1.5  to  2.0  parts  per  million  of  manganese.  The  free  carbon 
dioxide  was  first  removed  by  passing  the  water  through  crushed  mar- 
ble. The  treated  water  was  free  from  manganese  and  neutral.  The 
hardness  was  slightly  increased  by  solution  of  calcium  in  the  neu- 
tralization of  free  carbon  dioxide.  Iron  is  removed  with  the  manga- 
nese in  the  process.  As  the  cost  of  installation  of  a  permutit  plant  is 
high  it  has  been  introduced  in  only  a  few  places  for  large-scale  opera- 
tions. 

1Gans,  Robert,  Die  Mangangefahr  bei  der  Benutzung  von  Grundwasser  zur  Trinkwasser- 
versorgung  und  deren  Beseitigung :      Chem.  Ind.,  S3,  48-51,  66-9  (1910). 
2Oesterr.  Chem.  Tech.  Ztg.  26,  Bohrtechnicker  section  16,  178. 


METHODS  OF  REMOVAL  43 

The  oxide,  Mn207,  is  considered  the  basis  of  the  removal  process 
in  a  pamphlet  distributed  by  The  Permutit  €o.  entitled  "The  chem- 
istry of  permutit.  '  '  The  reactions  presented  are  as  follows,  the  letter 
p  representing  permutit  : 

p-Na2-fMnCl2=p-Mn-f2NaCl 
p-Mn-j-2KMnO4=p-K2MnO  :Mn2OT 
p-K2MnO  . 


The  question  of  whether  the  reduction  is  to  MnO,  Mn02,  or 
Mn203  is  considered  in  this  discussion  to  be  undecided. 

Another  method  of  removing  manganese  was  patented  by  Pap- 
pel1  who  filtered  the  manganese-bearing  water  through  granular  py- 
rolusite.  The  material  finally  may  lose  its  power  of  removal, 
but  the  power  is  restored  by  washing  it  with  ordinary  tap  water. 
Though  this  process  was  investigated  experimentally  at  Dresden  by 
Schmeitzner2  it  was  not  adopted  there  for  use  on  a  large  scale.  Man- 
ganese is  removed  from  the  city  supply  of  Breslau  by  this  method.  A 
natural  sand  containing  pyrolusite  is  used  as  the  medium. 

Tillmans  and  Heublein,3  who  studied  the  theory  of  removal  of 
manganese  by  this  method,  found  that  when  pieces  of  pyrolusite  were 
allowed  to  stand  suspended  in  tubes  containing  a  solution  of  man- 
ganous  sulphate  solidified  with  gelatin,  after  which  ammonia  was 
poured  on  the  surface,  the  Liesegang  rings  in  the  vicinity  of  the  pieces 
of  pyrolusite  were  absent.  The  power  of  this  substance  to  absorb  and 
remove  manganous  salts  from  solutions  was  thus  shown.  When  pure 
manganese  dioxide  was  allowed  to  react  with  a  dilute  solution  of  man- 
ganous sulphate  the  free  acid  formed  was  equivalent  to  the  manga- 
nese removed.  .  They  consider  the  reaction  to  be  : 
MnO2-fMnSO4=Mn2O,+SO, 

Tillmans,4  reviewing  his  former  work  in  a  later  article  states 
that  manganese  dioxide  is  the  essential  medium  which  removes  man- 
ganese in  the  permutit  process. 

Other  methods  for  the  removal  of  manganese  have  been  proposed, 
in  which  chemicals  to  precipitate  the  element  are  added  to  the  water. 
Luhrig  and  Blasky,5  who  were  among  the  first  to  experiment  on  this 

1Pappel,  Alfred,  Entmanganen  von  Wasser,  German  pat.  241,  571:  Chem.  Ztg.  Rep., 
36,  7  (1912). 

2Schmeitzner,  R.,  [The  removal  of  manganese  from  ground  water]  :  Techn.  Gem.  bl., 
16,  343;  Wasser  u.  Abwasser,  7,  376-7  (1914);  through  C.  A.  8,  974  (1914). 

3Tillmans,  J.,  and  Heublein,  O.,  Versuche  zur  Theorie  der  Entmanganung  von  Grund- 
wasser:  Z.  Nahr.  Genussm.,  27,  253-64  (1914). 

4Tillmans,  J.,  Uber  die  Entmanganung  von  Trinkwasser:    J.  Gasbel.,  57,  713-24   (1914). 

5Luhrig,  H.,  and  Blasky,  A.,  Mangan  im  Grundwasser  der  Breslauer  Wasserleitungen 
und  die  Frage  der  Abscheidung  des  Mangansulfates  aus  demselben:  Chem.  Ztg.,  31.  255-7 
U907). 


44  MANGANESE  IN  WATER  SUPPLIES 

problem,  suggested  the  addition  of  potassium  permanganate  or  lime 
to  precipitate  the  manganese.  These  chemical  methods  have  not  come 
into  practical  use.  A  study  of  them  was  undertaken  by  the  writer  to 
determine  the  chemistry  of  the  processes  and  especially  that  in  which 
the  water  is  treated  by  aeration. 

Manganese  Permutit 

Specimens  of  manganese  permutit,  kindly  furnished  by  The 
Permutit  Co.  for  the  study,  consist  of  irregular  black  grains  2  or  3 
millimeters  in  diameter.  When  these  are  crushed,  a  white  core  is 
noted  in  the  center  of  each.  A  specimen  of  the  permutit  was  ground, 
dried  at  105  °C.,  and  analyzed.  Manganese  was  determined  as  the 
pyrophosphate.  Available  oxygen  was  determined  by  distilling  the 
chlorine  evolved  on  treatment  with  hydrochloric  acid  into  potassium 
iodide  and  titrating  the  liberated  iodine.  The  analysis  is  as  follows : 

TABLE  26. — ANALYSIS  OF  MANGANESE  PERMUTIT. 

Potassium  oxide  (K2O) 4.00 

Sodium    oxide   (Na2O) 4.37 

Calcium    oxide    (CaO) 1.87 

Magnesium  oxide   (MgO) .17 

Ferric    oxide  (FeaO8) 42 

Alumina      (AlaO,) 22.72 

Silica  (Si02)    38.28 

Manganous  oxide   (MnO) 10.37 

Available  oxygen   (O) 1.94 

Water    .  15.34 


99.48 

This  specimen  of  permutit  had  been  prepared  by  treating  sodium 
permutit  with  manganous  salt  and  afterward  with  potassium  perman- 
ganate. The  determined  content  of  manganese,  calculated  as  MnO, 
is  10.37  per  cent;  the  amount  of  available  oxygen,  which  should  de- 
termine the  degree  of  oxidation  of  the  manganese,  was  found  to  be 
1.94  per  cent.  The  theoretical  percentage  of  available  oxygen  which 
should  have  been  obtained  if  the  manganese  had  been  present  in  each 
form  is  as  follows : 

Available 

Oxygen 

(O). 

MnO,  for  10.37  per  cent  of  MnO  as — 2.37 

Mn203    1.17 

Mn,04    78 

MnO none. 


MANGANESE  PERMUTIT  45 

As  1.94  per  cent  of  available  oxygen  was  found,  the  oxide  is  high- 
er than  MnO,  Mn304,  and  Mn203,  but  not  so  high  as  Mn02. 

In  order  to  determine  what  compounds  of  manganese  effected  the 
removal  specimens  of  ground  manganese  permutit  were  regenerated 
to  the  greatest  possible  degree,  and  exhausted  to  the  least  possible 
degree.  One  portion  was  treated  with  a  saturated  solution  of  potas- 
sium permanganate  and  agitated  in  a  shaking  machine,  for  several 
days.  It  was  then  allowed  to  stand  for  two  weeks,  at  the  end  of  which 
time  the  solid  material  was  removed  by  filtration,  washed  free  from 
permanganate,  dried,  and  analyzed.  The  composition  was  as  follows : 

TABLE  27. — ANALYSIS  OP  SPECIALLY  TREATED  MANGANESE  PERMUTIT. 

Potassium  oxide   (K2O) 10.26 

Sodium    oxide  (Na2O) 1.00 

Calcium  oxide  (CaO) 1.28 

Magnesium  oxide   (MgO) trace 

Ferric    oxide  (Fe2O3) 66 

Alumina    (A12O3)    22.62 

Silica  (SiO2)    39.09 

Manganous    oxide  (MnO) 12.30 

Available  oxygen   (O) 2.49 

Water    .  10.83 


100.53 

The  empirical  formula  calculated  from  the  above  analysis  is 
3R20  3MnOx-4Al203-12Si02-llH20,  in  which  R,0  represents  the 
oxides  of  the  alkalies  and  alkaline  earths.  After  regeneration  the 
amount  of  manganese  calculated  as  MnO  was  found  to  be  12.30  per 
cent,  and  the  available  oxygen,  2.49  per  cent.  The  theoretical  quan- 
tity of  available  oxygen,  if  all  the  manganese  had  been  in  the  form  of 
Mn02,  would  have  been  2.77  per  cent.  This  shows  that  regeneration 
has  increased  the  available-oxygen  ratio,  or  the  degree  of  oxidation  of 
the  manganese,  but  that  it  is  still  somewhat  lower  than  the  theoretical 
for  manganese  dioxide. 

There  are  several  reasons  why  a  quantity  of  available  oxygen 
smaller  than  the  theoretical  might  be  obtained.  The  treatment  may 
not  have  been  continued  sufficiently  long  to  complete  the  reaction.  All 
the  manganese  which  is  present  in  an  insoluble  silicate  of  this  charac- 
ter probably  can  not  be  reached  and  attacked  by  the  permanganate 
because  of  the  physical  structure  of  the  material.  Moreover,  Morse, 
Hopkins,  and  Walker1  have  shown  that  manganese  dioxide  loses  a 


JMorse,  H.  N.,  Hopkins,  A.  J.,  and  Walker,  M.  S.,  The  reduction  of  permanganic  acid 
by  manganese  superoxide :  Am.  Chem.  J.,  18,  401-19   (1896). 


46  MANGANESE  IN  WATER  SUPPLIES 

small  quantity  of  its  oxygen  on  drying  in  the  air  and  that  compounds 
like  MnO  -50Mn02  are  obtained.  For  this  reason  a  content  of  avail- 
able oxygen  slightly  lower  than  actually  present  would  be  found  by 
analysis. 

The  large  percentage  of  potassium  and  the  small  percentages  of 
sodium,  calcium,  and  magnesium  compared  with  the  smaller  per- 
centage of  potassium  and  the  larger  percentages  of  sodium,  calcium, 
and  magnesium  found  before  regeneration  in  this  specimen  are  par- 
ticularly interesting.  This  is  explained  by  the  fact  that  these  metals 
are  replaceable,  and  that  treatment  with  potassium  permanganate 
has  not  only  brought  about  oxidation  of  the  manganese,  but  has  at 
the  same  time  effected  replacement  of  the  other  metals  with  potassium. 
The  effect  of  replacement  can  be  represented  graphically  by  the  re- 
action : 


(K,  Na,  Ca)  Permutit-f3K  MnO4=K*  Permutit-fjCa(MnO4)2+NaMnO4 

Oxidation  of  the  manganese  in  the  zeolite  takes  place  with  the  re- 
placement, giving  manganese  dioxide  as  the  limit  of  oxidation  and 
not  such  higher  oxides  as  MnO  -Mn207  and  2MnO  -Mn207,  as  suggested 
by  Gans.1 

A  portion  of  this  regenerated  sample  was  then  shaken  with  a 
strong  solution  of  manganous  sulphate  in  the  same  manner.  After 
washing  and  drying  it  was  found  to  have  the  composition  shown  in 
Table  28. 

TABLE  28.  —  ANALYSIS  OF  SPECIALLY  TREATED  REGENERATED  MAN- 
GANESE PERMUTIT. 

Potassium  oxide   (K2O)  .....................................       3.15 

Sodium    oxide   (Na2O)  ......................................       2.20 

Calcium  oxide  (CaO)  ........................................  54 

Magnesium  oxide  (MgO)  ...................................    Trace 

Ferric    oxide  (Fe2O8)  ........................................  50 

Alumina    (A12OS)    ...................  .  ......................     23.05 

Silica  (SiOa)    ..............................................     37.37 

Manganous  oxide   (MnO)  ...................................     15.05 

Available  oxygen  (O)  .....................................         2.00 

Water    ....................................................     14.76 

99.62 

The  empirical  formula  calculated  from  this  analysis  is,  3/2 
E20  4MnOx  :4A1203  •  12Si02  -16H20. 


,  Robert,  Die  Mangangefahr  bei  der    Benutzung    von    Grundwasser    zur    Trink- 
wasserversorgung  und  deren  Beseitignng :  Chem.  Ind.,  33,  48-51,  66-9  (1910). 


MANGANESE  PERMUTIT  47 

The  determined  content  of  available  oxygen  was  2.00  per  cent. 
The  theoretical  content  of  available  oxygen  for  Mn203,  the  oxide  next 
lower  than  Mn02,  is  1.70  per  cent.  It  was  subsequently  found, 
however,  that  in  the  analysis  of  the  reduced  material,  oxygen  was 
taken  up  while  the  substance  was  being  dried  in  the  air.  The  content 
of  2.00  per  cent,  therefore,  is  probably  too  great,  and  little  significance 
should  be  attached  to  it. 

The  low  percentages  of  sodium  and  potassium,  and  the  high  per- 
centage of  manganese  are  interesting,  especially  when  they  are  com- 
pared with  corresponding  figures  for  the  regenerated  specimen.  A 
replacement  as  well  as  a  reduction  again  has  taken  place.  The  replace- 
ment is  the  substitution  of  manganese  for  the  sodium  and  potassium 
of  the  permutit,  which  can  be  represented  by  the  reaction: 

++--  H 

Ka  Permutit-f  MnSO4=Mn  Permutit-f-K2SO4 

The  extent  to  which  this  reaction  takes  place  is  governed  by  the 
concentration  of  manganese  in  the  solution.  As  the  concentration  is 
usually  very  low  this  reaction  is  relatively  unimportant  and  it  must 
take  place  to  only  very  slight  extent.  Coincident  with  this  reaction 
the  manganese  dioxide  is  reduced  to  a  lower  oxide  by  the  manganous 
salt  thus:  Mn02+MnS04=>Mn2Ox+S03.  This  is  the  basic  reaction 
involved  in  the  permutit  process. 

The  acid  which  is  formed  when  the  manganese  is  removed  is 
undoubtedly  neutralized  by  the  alkaline  silicate,  for  Gans1  has  shown 
that  free  acid,  even  carbonic  acid,  has  a  solvent  action  on  permutit. 

Manganese  permutit  consists  of  a  zeolite  with  which  a  layer  of 
manganese  dioxide  is  incorporated.  When  a  manganese-bearing 
water  is  filtered  through  this  medium  the  manganese  is  removed  from 
the  water  by  the  formation  of  a  lower  oxide  of  manganese  by  reaction 
between  the  manganese  in  the  water  and  the  manganese  dioxide  in  the 
permutit.  At  the  same  time  the  alkali  or  alkaline-earth  of  the  silicate 
is  replaced  by  the  manganous  compound  of  the  water.  The  replace- 
ment is  of  minor  importance,  and  the  slight  extent  to  which  it  takes 
place  is  dependent  on  the  concentration  of  manganese  in  the  water. 
Manganese  is  added  to  the  permutit  not  only  when  manganese  per- 
mutit is  regenerated  by  potassium  permanganate  but  also  when  man- 
ganese is  removed  from  water  by  the  regenerated  permutit ;  therefore, 
the  content  of  manganese  dioxide  increases  and  the  filter  medium  ap- 
proaches in  composition  pure  manganese  dioxide  with  each  successive 
regeneration  and  reduction.  As  the  zeolite  can  not  increase  in  amount 


48 


MANGANESE  IN  WATER  SUPPLIES 


with  successive  reductions  and  regenerations  the  replacement  effect 
must  become  less  and  less  as  the  substance  is  used.  These  conclusions 
are  in  entire  accord  with  that  reached  independently  by  Tillmans1 — 
that  the  action  of  manganese  permutit  is  realty  the  action  of  manga- 
nese dioxide. 

Sand  Filtration 

Some  preliminary  experiments  made  by  filtering  an  aerated  arti- 
ficially prepared  manganese-bearing  water  through  a  small  sand  filter 
showed  that  no  removal  of  manganese  was  effected.  A  mechanical  fil- 
tration plant  has  been  installed  at  Mount  Vernon,  111.,  however,  for  the 


Figure  2. — Experimental  sand  filters  for  the  removal  of  manganese. 

purpose  of  removing  manganese  as  well  as  effecting  hygienic  purifica- 
tion of  a  surface  water,  and  analyses  of  the  water  some  months  after 
installation  of  the  mechanical  filters  showed  that  manganese  was  being 
removed  by  this  plant.  Manganese  is  also  removed  in  a  filter  plant  at 
Anna,  111.,  designed  for  hygienic  purification  of  a  surface-water  sup- 
ply. These  results  seemed  contradictory  to  the  negative  results  ob- 
tained on  a  small  scale.  Yet,  as  manganese  dioxide  had  been  used 


Tillmans,  J.,  Uber  die  Entmanganung  von  Trinkwasser:  J.  Gasbel.,  57,  713-24  (1914). 


SAND  FILTRATION  49 

successfully  for  removal  of  manganese  and  as  this  compound  is  the 
basic  part  of  manganese  permutit  it  was  concluded  that  manganese 
dioxide  was  the  principal  factor  in  the  removal  of  manganese  in  suc- 
cessful sand  filtration. 

Two  filters  were,  therefore,  prepared  for  experimental  use.  The 
apparatus  (See  Figure  2)  consisted  of  two  gas- washing  cylinders 
(A,  A)  connected  at  their  tops  by  a  siphon  to  a  large  carboy  (B) 
holding  the  water  to  be  treated.  The  rate  of  filtration  could  be  so 
adjusted  by  two  stopcocks  (S,  S)  that  both  niters  would  deliver  their 
effluents  at  the  same  rate.  A  glass  tube  (€)  extending  to  the  bottom 
of  the  carboy  provided  means  for  admitting  compressed  air  for  aera- 
tion. 

Each  filter  was  filled  with  one  liter  of  clean  high-grade  filter 
sand,  having  an  effective  size  of  0.50  millimeter  and  a  uniformity  co- 
efficient of  1.32.  One  filter  was  treated  successively  with  solutions 
of  manganous  sulphate,  sodium  hydroxide,  and  potassium  permangan- 
ate. After  two  or  three  treatments  a  thin  film  of  black  oxide  of  man- 
ganese had  formed  on  the  grains  of  sand.  The  filter  was  then  washed 
with  water  until  an  effluent  free  from  manganese  was  obtained.  The 
other  filter  was  used  without  such  treatment.  The  apparatus  consist- 
ed, therefore,  of  two  filters  working  in  parallel,  one  containing  sand 
only,  and  the  other  containing  sand  which  had  been  slightly  coated 
with  manganese  dioxide.  As  the  depth  of  sand  in  each  was  35  centi- 
meters the  filtering  area  of  each  was  28  square  centimeters. 

The  removal  of  manganese  in  a  manganese-removal  filter, 
depends  on  the  contact  of  the  manganous  compound  with  man- 
ganese dioxide;  consequently,  the  rate  of  filtration  should  be  ex- 
pressed in  terms  of  volume  of  water  filtered  per  volume  of  fil- 
ter medium  and  not  per  area  of  filter  surface.  The  rate  varied 
slightly  in  these  experiments,  but  it  was  so  adjusted  that  a  volume 
of  water  equal  to  the  volume  of  the  filter  medium  was  filtered  in 
twenty  minutes.  The  waters  used  were  prepared  by  dissolving  com- 
pounds of  iron  and  manganese  in  tap  water,  distilled  water,  and  a 
mixture  of  the  two.  The  tap  water  is  a  bicarbonate,  iron-bearing 
water  from  drift  wells.  The  determinations  in  Table  29  represent  the 
character  of  the  tap  water  used  in  reference  to  a  discussion  of  re- 
moval of  manganese. 

TABLE  29. — CHARACTER  OF  TAP  WATER  USED  IN  EXPERIMENTATION 
ON  REMOVAL  OF  MANGANESE. 

Parts  per  million. 

Turbidity    5 

Color    .  15 


50  MANGANESE  IN  WATER  SUPPLIES 

Eesidue  on  evaporation  370 

Chloride .3 

Alkalinity  as  CaCO3  in  presence  of  methyl  orange 355 

Free  carbon  dioxide  40 

Iron   2.0 

Manganese none 

Total  hardness 300 

Dissolved  oxygen none 

Oxygen  consumed   4.8 

The  first  artificial  water  was  prepared  by  adding  5  parts  per  mil- 
lion of  manganese  as  MnS044H20  to  a  mixture  of  about  equal  parts 
of  tap  water  and  distilled  water.  The  water  was  aerated  by  blowing 
air  through  it  for  one  hour  and  allowing  to  stand  for  two  hours.  It 
was  then  filtered  through  the  apparatus,  and  manganese,  iron,  car- 
bon dioxide,  dissolved  oxygen,  and  alkalinity,  were  determined  in 
samples  taken  at  two-hour  intervals.  The  results  are  shown  in  Table 
30. 

TABLE  30. — REMOVAL  OF  MANGANESE  BY  AERATION  AND  FILTRA- 
TION OF  A  MIXTURE  OF  TAP  WATER  AND  DISTILLED  WATER  CONTAINING  5 
PARTS  PER  MILLION  OF  MANGANESE. 


[Parts  per  million.] 


Water  filtered 

through  — 

Sand. 

Sand  coated  with 
manganese  dioxide. 

AT  ST 

\RT 

4  8 

4  4 

o 

4 

.05 

o 

Alkalinity        

200 

200 

196 

Dissolved  oxygen  

7.4 

7.2 

6  2 

Carbon  dioxide  

4.0 

2.0 

2.0 

AFTER  2  HOURS 

'  OPERATION 

Manganese  

4.8 

4.8 

o 

Iron  

.4 

.05 

o 

Alkalinity 

200 

200 

194 

Dissolved  oxygen  

7.2 

7.4 

6.6 

AFTER  4  HOURS 

'   OPERATION 

Manganese   

4  8 

4  4 

o 

Iron    

05 

o 

Alkalinity  

200 

200 

194 

7  4 

7  4 

6  6 

Carbon  dioxide  

2.0 

4.0 

6.0 

AFTER  6  HOURS 

'  OPERATION 

4  8 

4  0 

05 

Iron  

.4 

05 

o 

Alkalinity  

200 

200 

192 

Dissolved  oxygen  

7.5 

7.5 

6.8 

SAND  FILTRATION 


51 


Aeration  decreased  the  content  of  free  carbon  dioxide  to  2  to  4 
parts  per  million,  and  increased  the  content  of  dissolved  oxygen  to  7.4 
parts  per  million.  Filtration  through  sand  removed  practically  all  the 
iron,  but  caused  practically  no  change  in  the  content  of  manganese, 
dissolved  oxygen,  and  alkalinity.  Filtration  through  sand  coated  with 
manganese  dioxide,  on  the  other  hand,  removed  all  manganese  and 
iron,  has  decreased  the  content  of  dissolved  oxygen  an  average  of  .8 
part  per  million  and  the  alkalinity  an  average  of  .4  part  per  million. 
These  results  indicate  that  aeration  and  sand  nitration  do  not  remove 
appreciable  amounts  of  manganese.  In  the  manganese-dioxide  filter  the 
manganous  compound  evidently  combines  with  the  manganese  dioxide 
to  form  a  lower  oxide  exactly  as  in  the  pyrolusite  and  the  permutit 
processes.  When  manganese  is  removed  the  equivalent  of  free  acid 
that  is  formed  causes  a  corresponding  decrease  in  the  alkalinity.  This 
decrease  should  theoretically  be  10  parts  per  million  when  5  parts  per 
million  of  manganese  is  removed,  whereas  the  actual  decrease  was 
only  4  parts  per  million.  The  disappearance  of  0.8  part  per.  million 
of  dissolved  oxygen  in  the  manganese-dioxide  filter  is  undoubtedly 
due  to  oxidation  of  the  lower  oxide  of  manganese  to  manganese  di- 

TABLE  31. — KEMOVAL  OP  MANGANESE  BY  AERATION  AND  FILTRATION, 
OF  TAP  WATER  CONTAINING  10  PARTS  PER  MILLION  OF  MANGANESE. 

[Parts  per  million.] 


Water  filtered 

through  — 

Determinations. 

Unfiltered  water. 

Sand. 

Sand  coated  with 
manganese  dioxide. 

AT  ST./ 

LET 

Manganese  '.  .  .  . 

10.5 

9.0 

0.1 

Iron    

.8 

.0 

.0 

Alkalinity  

356 

354 

342 

5.3 

3.4 

5.0 

4 

'6 

8 

AFTER  2  HOURS 

'  OPERATION 

Manganese               

10 

10.5 

.1 

Iron    

.8 

.0 

.0 

Alkalinity  

358 

356 

344 

5  6 

4  2 

4  1 

Carbon  dioxide  

6 

8 

12 

AFTER  4  HOURS 

'   OPERATION 

Manganese            

9  5 

10  0 

o 

Iron    

8 

1 

o 

Alkalinity  

358 

358 

342 

Dissolved  oxygen  

5.6 

4.0 

4.0 

AFTER  6  HOURS 

'  OPERATION 

10  0 

10  0 

o 

Iron    

8 

o 

o 

Alkalinity  

356 

354 

340 

5.7 

4.5 

3.5 

52 


MANGANESE  IN  WATER  SUPPLIES 


oxide.  If  this  were  quantitative  the  removal  of  5  parts  of  manga- 
nese should  reduce  the  content  of  dissolved  oxygen  1.6  parts;  the 
actual  reduction  was,  however,  only  08  part. 

In  another  series  of  experiments  (See  Table  31)  tap  water  in 
which  10  parts  per  million  of  manganese  as  MnS044H20  had  been 
dissolved  was  used. 

These  results  are  generally  similar  to  those  in  Table  30.  Filtra- 
tion through  sand  removed  iron,  but  did  not  detectibly  decrease  man- 
ganese. The  content  of  dissolved  oxygen  was  decreased  throughout 
more  than  one  part  per  million  by  passage  through  the  niters,  even  in 
the  experiment  in  which  no  removal  of  manganese  apparently  took 
place.  Filtration  through  sand  coated  with  manganese  dioxide  re- 
moved all  manganese  and  iron,  decreased  alkalinity  14  parts  per  mil- 
lion, and  decreased  dissolved  oxygen  about  the  same  extent  to  which 
it  was  decreased  in  the  sand  filter. 

In  order  to  determine  the  effect  of  adding  a  coagulant,  2  grains 
per  gallon  of  alum  was  added  to  the  artificial  water,  the  water  was 
then  aerated,  and  allowed  to  settle  one  hour  as  in  the  other  series.  The 
results  obtained  (See  Table  32)  indicate  that  little  change  is  caused 

TABLE  32. — REMOVAL  OF  MANGANESE  BY  AERATION  AND  FILTRATION, 

OF  ARTIFICIAL  WATER  CONTAINING  5  PARTS  PER  MILLION  OF  MANGANESE 
AND  2  GRAINS  PER  GALLON  OF  ALUM.  ALKALINITY  BEFORE  TREATMENT 

356  PARTS. 

[Parts  per  million.] 


Determinations. 

Unfiltered  water. 

Water  filtered  through  — 

Sand. 

Sand  coated  with 
manganese  dioxide. 

AT  START 

Manganese 

5.0 
.2 
340 
8.0 

4.8 
.0 
340 
6.5 

0.0 
.0 
328 
6.5 

Iron   

Alkalinity  

AFTER  2  HOURS'  OPERATION 

5.0 
.2 
338 
8.0 

4.7 
.0 
338 
7.2 

.0 
.0 
330 
6.0 

Iron            . 

Alkalinity   

Dissolved  oxygen  

AFTER  4  HOURS'   OPERATION 

5.0 
.2 
340 
8.0 

4.8 
.05 
338 
7.0 

.0 
.0 
328 
6.2 

Iron 

Alkalinity  

Dissolved  oxygen  

AFTER  6  HOURS'  OPERATION 

Manganese 

4.8 
.2 
336 
7.5 

5.0 
.2 
334 
7.0 

.0 
.0 
330 
6.0 

Iron  

Alkalinity  

SAND  FILTRATION 


53 


by  addition  of  the  coagulant.  Complete  removal  of  manganese  was 
obtained  by  filtration  through  sand  coated  with  manganese  dioxide 
but  practically  no  removal  by  filtration  through  sand  alone. 

The  action  in  presence  of  both  iron  and  manganese  was  studied 
by  treating  a  mixture  of  distilled  water  and  tap  water  in  which  10 
parts  per  million  of  manganese  as  MnS044H20  and  10  parts  per  mil- 
lion of  iron  as  FeS04-(NH4)2S046H20  had  been  dissolved  (See  Table 
33).  After  this  water  had  been  aerated  it  had  a  high  reddish-brown 
turbidity  caused  by  precipitated  ferric  hydroxide.  Treatment  of  this 
solution  by  filtration  through  sand  alone  resulted  in  complete  removal 
of  iron  but  no  removal  of  manganese.  Treatment  of  it  by  filtration 
through  sand  coated  with  manganese  dioxide,  however,  completely  re- 
moved manganese  and  iron.  The  alkalinity  was  not  decreased  by  pass- 
age through  either  filter ;  this  is  not  in  accordance  with  the  theory  as 
the  removal  should  have  decreased  the  alkalinity  by  an  amount  equiva- 
lent to  the  manganese  removed.  This  apparent  discrepancy  might 
be  accounted  for  either  by  the  presence  of  small  amounts  of  substances 
capable  of  neutralizing  free  acid  in  the  sand,  or  by  oxidation  of  the 
manganous  compound  to  a  marked  degree  in  the  aeration  and  yet  to 
a  degree  insufficient  to  form  an  insoluble  compound. 

TABLE  33. — REMOVAL  OF  MANGANESE  BY  AERATION  AND  FILTRATION 
OF  A  MIXTURE  OF  TAP  WATER  AND  DISTILLED  WATER  CONTAINING  10 
PARTS  PER  MILLION  OF  MANGANESE  AND  10  PARTS  PER  MILLION  OF  IRON. 

[Parts  per  million.] 


Determinations. 

Unfiltered  water. 

Water  filtered  through  — 

Sand. 

Sand  coated  with 
manganese  dioxide. 

AT  START 

10.0 
5.0 
24 
7.3 

10.0 
.1 
26 

7.4 

0.0 
.0 
30 
2.9 

Alkalinity        

Dissolved  oxygen  

AFTER  2   HOURS'  OPERATION 

9.5 
4.8 
24 
7.6 

10.0 
.0 
24 
7.5 

.0 

.0 
30 
2.8 

Alkalinity        

Dissolved  oxygen  

AFTER  4  HOURS'  OPERATION 

Manganese  

9.0 
5.0 

7.6 

10.0 
.0 
24 

7.8 

.0 

.0 
30 
6.0 

Alkalinity                 .    ... 

Dissolved  oxygen  

AFTER  6  HOURS'  OPERATION 

Manganese  

10.0 
4.8 
24 
7.6 

9.0 
.0 
24 
7.8 

.0 
.0 
28 
7.0 

Alkalinity   

Dissolved  oxygen  

54  MANGANESE  IN  WATER  SUPPLIES 

Though  no  removal  of  manganese  by  nitration  through  sand 
could  be  detected  by  analysis  the  upper  part  of  the  sand  became 
discolored  by  a  slight  deposit  of  manganese  dioxide  after  the  filter  had 
been  used  for  some  time.  This  shows  that  there  must  have  been  some 
slight  but  continual  removal  of  manganese  by  aeration  and  nitration. 
This  slight  deposit  would  rapidly  aid  in  removal  of  more  and  more 
manganese  until  sufficient  manganese  dioxide  would  have  been  de- 
posited to  remove  completely  the  manganese  from  water  filtered 
through  it ;  the  process  might  be  erroneously  considered  to  be  simply 
one  of  aeration  and  filtration  through  sand  when  in  reality  it  is  a 
catalysis  by  manganese  dioxide. 

Manganese-Removal  Plants  in  Illinois 

Manganese  is  efficiently  removed  from  surface-water  supplies  by 
filtration  through  sand  coated  with  manganese  dioxide  at  two  plants 
in  Illinois.  One  of  these  filter  plants  was  installed  for  removal  of 
manganese  as  well  as  for  hygienic  purification  of  the  water,  and  the 
other  was  installed  for  hygienic  purification  only,  the  presence  of 
manganese  in  the  water  not  being  suspected.  There  was  evidence  of 
unsatisfactory  removal  of  manganese  for  some  time  after  the  installa- 
tion of  these  plants,  but  efficient  removal  resulted  after  a  period  had 
elapsed  for  the  deposition  of  sufficient  manganese  dioxide  in  the  fil- 
ters. As  no  similar  observations  have  been  reported  a  descrip- 
tion of  these  two  plants  with  some  of  the  operating  results  are  pre- 
sented. 

REMOVAL  OF  MANGANESE  AT  ANNA. 

The  waterworks  of  Anna  State  Hospital,  in  southern  Illinois,  are 
located  about  2  miles  from  Anna  and  about  3i/>  miles  from  the  hos- 
pital buildings.  The  plant  was  put  in  operation  in  January,  1914. 

About  half  the  supply  is  derived  from  a  2,000,000-gallon  impound- 
ing reservoir,  on  Kohler  Creek,  which  is  fed  by  springs  which  bubble 
up  over  the  bottom  of  the  reservoir  as  well  as  by  rainfall  on  the  water- 
shed. The  other  half  of  the  supply  used  is  taken  from  Wilson  Creek, 
a  near-by  stream. 

Mineral  analyses  of  these  two  sources  of  supply  are  given  in 
Table  34. 

The  supply  from  Wilson  Creek  contains  practically  no  mangan- 
ese, but  that  from  the  reservoir  contains  a  large  amount. 

The  content  of  manganese  of  water  from  the  reservoir  varies 
widely.  Turbidity,  color,  and  bacterial  content  are  low  compared  with 
those  of  other  surface  waters  of  Illinois.  The  water  contains  much 


REMOVAL  OF  MANGANESE  AT  ANNA 


55 


TABLE  34. — MINERAL  ANALYSES  OF  THE  WATER  SUPPLY  OF  ANNA 
STATE  HOSPITAL,  OCTOBER,  1914. 

[Parts  per  million.] 


Wilson  Creek. 

Reservoir. 

IONS 
Potassium   (K)                                     

5.6 

4.7 

Sodium  (Na)             .             

17.8 

11.8 

12.6 

7.5 

Calcium  (Ca)           

78.6 

43.9 

Iron  (Fe)        

1.0 

0.6 

Manganese  (Mn)  

Trace 

1.4 

Alumina  (AbOs)  

1.2 

3.0 

Silica  (SiOj) 

18.2 

6.3 

Nitrate  (NOs) 

5.3 

4.0 

Chloride  (Cl) 

3.0 

1.0 

Sulf  ate  (  SCU)  

5.2 

11.1 

HYPOTHETICAL  COMBINATIONS 
Potassium  nitrate  (KNOs)  

8  6 

6  5 

Potassium  chloride  (KC1)  

6  3 

2  i 

Potassium  sulfate  (K2SO<)  

2  4 

Sodium  sulfate  (Na2SO4)  

7  7 

14  5 

35  2 

10  8 

43  6 

26  0 

196  2 

109.8 

Iron  carbonate  (FeCOs) 

2  o 

1  2 

Trace 

2  9 

1  2 

3  0 

Silica    (SiOz) 

18  2 

6.3, 

Bases  

2.0 

0.0 

Total  

321.0 

185.5 

dissolved  oxygen  and  very  little  carbon  dioxide.  Determinations 
showed  9.8  parts  per  million  of  dissolved  oxygen,  which  is  high,  but 
only  3  parts  per  million  of  carbon  dioxide  when  the  temperature  of 
the  water  was  20  °€.  The  water  is  treated  by  ordinary  mechanical 
nitration.  About  one  grain  per  gallon  of  alum  is  added,  after  which 
the  water  passes  through  a  sedimentation  basin  affording  retention 
for  4  hours.  Calcium  hypochlorite  is  added  at  the  outlet  of  the  sed- 
imentation basin  at  the  rate  of  0.2  part  per  million  of  available  chlor- 
ine, after  which  the  water  passes  to  the  niters.  There  are  3  concrete 
filter  units,  each  having  a  capacity  of  300,000  gallons  per  24  hours. 
The  nominal  rate  of  filtration  is  125,000,000  gallons  per  acre  per  day. 
The  filters  contain  9  inches  of  gravel  and  30  inches  of  sand,  which 
had,  when  it  was  put  in  place,  an  effective  size  of  0.55  millimeter  and 
a  uniformity  coefficient  of  1.43. 

The  presence  of  manganese  in  a  surface  water  containing  so  much 
dissolved  oxygen  was  not  suspected  until  complaint  was  received  that 
the  filtered  water  was  causing  unsightly  stains  on  white  plumbing 
fixtures  and  was  staining  fabrics  in  the  laundry  a  pale  yellow.  A  con- 
tent of  12  parts  per  million  of  manganese  was  found  in  the  raw  water 
July  22,  1914.  Subsequent  tests  showed  that  the  untreated  water 
from  the  impounding  reservoir  contained  7.5  parts,  July  30,  and  only 


56  MANGANESE  IN  WATER  SUPPLIES 

1.4  parts,  October  5.  The  water  of  Wilson  Creek  contained  0.05  part 
July  30  and  a  trace  October  5.  The  effluent  from  the  niters  con- 
tained 0.05  part  July  30  and  0.0  part  October  5.  The  analyses  of 
raw  and  filtered  water  indicate  an  efficient  removal  of  manganese  by 
the  treatment  which  the  water  received.  In  order  to  determine  the 
cause  of  this  removal  the  plant  was  visited  in  December,  1914,  and 
it  was  arranged  to  have  determinations  of  manganese  made  regularly 
in  the  laboratory  of  the  waterworks. 

It  was  impossible  to  obtain  representative  samples  of  the  raw 
water,  as  the  supplies  from  both  reservoir  and  Wilson  Creek  enter  the 
settling  basin  through  separate  inlets  in  such  manner  that  thoroughly 
mixed  samples  can  not  be  obtained  until  they  emerge  from  the 
basin.  Determinations  of  manganese  in /the  water  from  the  reservoir 
were  made  from  December  1  to  February  11,  and  one-half  of  this  value 
was  taken  as  the  true  content  of  manganese  of  the  raw  water  used. 
Determinations  were  made,  however,  from  February  11  to  May  4  on 
the  water  at  the  outlet  of  the  settling  basin.  It  was  found  that  the 
content  of  manganese  of  water  at  this  point  was  about  half  that  of 
water  from  the  reservoir.  As  the  determinations  were  made  by  the 
persulphate  method  on  50-cubic  centimeter  samples  only  figures  in 
the  first  decimal  place  are  significant.  The  results  obtained  on  samples 
from  December  1  to  May  4  are  shown  in  Table  35. 

Manganese  could  be  detected  in  the  filtered  water  in  only  7  of 
the  100  tests.  The  water  applied  to  the  filters  during  this  period  had 
a  content  of  manganese  of  0.0  to  1.0  part  per  million;  the  removal  is, 
therefore,  very  efficient.  The  content  of  manganese  of  the  reservoir 
supply  has  been  slowly  decreasing  since  the  summer  of  1914.  In 
March  and  April,  1915,  the  content  was  0.2  to  0.6  part  per  million, 
whereas  in  December,  1914,  it  was  1.0  to  2.0  parts  per  million.  In 
order  to  determine  the  effect,  if  any,  of  treatment  with  hypochlorite 
on  the  removal  of  manganese  the  application  of  that  chemical  was 
omitted  from  May  1  to  4,  1915.  As  an  effluent  free  from  manganese 
was  obtained  during  this  period  as  before  it  seems  apparent  that  as 
good  results  were  obtained  without  as  with  bleach. 

The  walls  of  the  concrete  filter  units  were  covered  with  a  layer 
of  manganese  dioxide,  which  in  appearance  resembled  asphaltum 
paint. 

Samples  of  the  filter  sand  were  collected  for  examination.  The 
sand  was  black  although  the  incrustation  was  not  sufficient  greatly  to 
increase  the  size  of  the  grains.  The  incrustation  was  somewhat  te- 
nacious, but  some  of  it  became  detached  when  the  sand  was  stirred  with 


REMOVAL  OP  MANGANESE  AT  ANNA 


57 


TABLE  35. — CONTENT   OF   MANGANESE   OP  RESERVOIR,  RAW,  AND 
FILTERED  WATER  AT  ANNA  STATE  HOSPITAL. 

[Parts  per  million.] 


Date. 

Reservoir 
water. 

Raw 
water. 

Filtered    1 
water. 

|       Date. 

Reservoir 
water. 

Raw 

water. 

Filtered 
water. 

1914 

1915 

Dec.    1 

1.5 

0.7 

0.2 

Mar.    1 

.4 

.2 

.0 

2 

2.0 

1.0 

.2 

2 

.4 

.1 

.0 

3 

1.0 

.5 

.0 

.5 

.2 

.2 

5 

1.2 

.6 

.1 

4 

.6 

.4 

.0 

7 

1.4 

.7 

.0 

5 

.4 

.2 

.0 

9 

.8 

.4 

.0 

g 

.4 

.2 

.1 

11 

1.2 

.6 

.0 

8 

.6 

.4 

.1 

13 

1.4 

.7 

.0 

9 

.4 

2 

.0 

15 

1.2 

.6 

.0 

10 

.2 

.0 

.0 

17 

1.8 

.9 

.0 

11 

.2 

.0 

.0 

19 

1.9 

1.0 

0 

12 

.2 

.0 

.0 

21 

1.7 

.8 

.0 

15 

.4 

.2 

.1 

23 

1.1 

.6 

.0 

16 

.4 

.1 

.0 

29 

2.0 

1.0 

.0 

17 

.6 

.2 

.0 

31 

1.7 

.9 

.0 

18 

.4 

.2 

.0 

19 

.4 

.1 

.0 

20 

.5 

.3 

.0 

22 

.4 

.2 

.0 

1915 

23 

.2 

.1 

.0 

Jan.    1 

1.6 

.8 

.0 

24 

.2 

.1 

.0 

3 

1.8 

.9 

.0 

25 

.2 

.0 

.0 

5 

2.1 

1.0 

.0 

26 

.4 

.2 

0 

7 

2.2 

1.1 

.0 

27 

.2 

.0 

.0 

9 

2.1 

1.1 

.0 

29 

.2 

.1 

.0 

11 

2.1 

1.1 

.0 

30 

.3 

.2 

.0 

13 

1.9 

.9 

.0 

31 

.3 

.0 

.0 

15 

1.8 

.9 

.0 

17 

1.7 

.9 

.0 

1915 

19 

.6 

.8 

.0 

Apr.    1 

0.2 

0.1 

0.0 

21 

.6 

.8 

.0 

2 

.2 

.0 

.0 

23 

.4 

.7 

.0 

3 

.1 

.0 

.0 

25 

.4 

.7 

.0 

5 

.2 

.2 

.0 

27 

.6 

.8 

.0 

6 

.3 

.1 

.0 

29 

1.8 

.9 

.0 

7 

.3 

.0 

.0 

31 

1.9 

1.0 

.0 

8 

.3 

.1 

.0 

9 

.4 

.2 

.0 

10 

.4 

.2 

.0 

12 

.4 

.1 

.0 

13 

.3 

.1 

.0 

1915 

14 

.3 

.1 

.0 

Feb.    1 

1.6 

0.8 

0.0 

15 

.4 

.2 

.0 

3 

1.4 

.7 

.0 

16 

.3 

.0 

.0 

5 

1.2 

.6 

.0 

17 

.5 

.3 

.0 

7 

1.6 

.8 

.0 

19 

.4 

.0 

.0 

9 

.8 

.4 

.0 

20 

.5 

.3 

.0 

11 

.5 

.3 

.0 

21 

.4 

.2 

.0 

13 

.4 

.2 

.0 

22 

.3 

.1 

.0 

15 

.2 

.1 

.0 

23 

.4 

.2 

.0 

*17 

.0 

0 

.0 

24 

.5 

.3 

.0 

•19 

.0 

.0 

.0 

26 

.3 

.2 

.0 

21 

.2 

1 

.0 

27 

.4 

.3 

.0 

23 

.2 

.0 

.0 

28 

.4 

.2 

.0 

25 

.2 

I 

.0 

29 

.5 

.3 

.0 

27 

.3 

.1 

.0 

30 

.3 

.1 

.0 

1915 

May    1 

.3 

.1 

.0 

3 

.6 

.4 

.0 

4 

1.0 

.5 

.0 

•Heavy  rains. 

water.  The  results  of  a  soil  analysis  of  the  sand  are  given  in  Table 
36.  Microscopic  examination  of  the  sediment  washed  from  the  sand 
grains  as  well  as  of  the  sediment  from  the  water  used  in  washing  the 
niters  showed  the  presence  of  diatoms  and  algae,  but  no  organisms 


58  MANGANESE  IN  WATER  SUPPLIES 

resembling  Crenothrix  were  found.  The  material  consisted  chiefly  of 
debris,  such  as  sand,  clay,  and  precipitated  hydroxides  of  manganese, 
iron,  and  aluminium. 

TABLE  36. — ANALYSIS  OF  FILTER  SAND,  ANNA  STATE  HOSPITAL. 

Insoluble  in  hydrochloric  acid  98.25 

Soluble  in  hydrochloric  acid    1.75 

Loss  on  ignition  .91 

The  soluble  portion 
consists  of: 

Ferric  oxide  (FeaO,)    16.8 

Alumina    (A12O,)    26.5 

Manganese  dioxide  (MnO2)    12.0 

Loss  on  ignition  54 

The  presence  of  manganese  dioxide  in  the  incrustation  on  the 
filter  sand  is  sufficient  to  account  for  the  removal  of  the  manganese 
from  the  water.  Some  experiments  were  undertaken,  however,  to  de- 
termine whether  manganese  dioxide  was  the  only  factor  in  the  process. 
The  two  experimental  filters,  one  containing  sand  and  the  other  sand 
impregnated  with  manganese  dioxide,  which  had  been  used  in  the 
former  experimental  work  with  artificially  prepared  waters,  were  used 
at  Anna  for  filtering  the  raw  water.  The  raw  water  contained  9.6 
parts  per  million  of  dissolved  oxygen  and  3  parts  per  million  of  free 
carbon  dioxide.  Its  temperature  was  20° C.  The  results  obtained  are 
shown  in  Table  37.  Complete  removal  of  manganese  was  obtained 
when  the  filter  containing  manganese  dioxide  was  used,  but  only  slight 
removal  of  manganese  was  obtained  when  the  filter  containing  sand 
alone  was  used.  This  filter,  however,  had  been  used  for  similar  work 
previously,  and  a  small  amount  of  manganese  dioxide  that  may  have 
been  present  on  the  sand  grains  doubtless  aided  the  removal. 

TABLE  37. — REMOVAL  OF  MANGANESE  BY  FILTRATION  OF  RAW 
WATER  AT  ANNA  STATE  HOSPITAL  THROUGH  EXPERIMENTAL  FILTERS  OF 
SAND  AND  OF  SAND  ARTIFICIALLY  COATED  WITH  MANGANESE  DIOXIDE. 

[Parts  per  million  of  manganese.] 


Raw  water. 

Water  filtered  through  — 

Sand. 

Sand  coated  with 
manganese  dioxide. 

1.0 
1.0 
1.0 
1.0 

0.8 
1.0 
.9 
.9 

0.0 
.1 
.0 
.0 

REMOVAL  OF  MANGANESE  AT  ANNA 


59 


In  order  to  test  the  theory  more  completely  the  raw  water  was 
filtered  through  another  pair  of  filters,  one  containing  some  unused 
sand  like  that  with  which  the  large  filters  at  Anna  are  filled  and  the 
other  containing  sand  from  the  filters  which  had  been  used  nearly  a 
year.  The  latter  sand  was  coal  black  due  to  the  coating  of  manga- 
nese dioxide  which  had  formed  on  the  grains.  The  results  of  these 
experiments  are  shown  in  Table  38.  -Complete  removal  of  manga- 
nese was  obtained  with  the  used  sand,  and  practically  no  removal  was 
obtained  with  the  unused  sand. 

TABLE  38. — REMOVAL  OF  MANGANESE  BY  FILTRATION  OF  RAW 
WATER  AT  ANNA  STATE  HOSPITAL  THROUGH  EXPERIMENTAL  FILTERS  OF 

UNUSED  SAND  AND  OF  SAND  AFTER  USE  NATURALLY  COATED  WITH  MANGA- 
NESE DIOXIDE. 

[Parts  per  million  of  manganese.] 


Raw  water. 

Water  filtered  through  — 

Unused  sand. 

Used  sand. 

1.0 
1.0 
1.0 
1.0 

1.0 
1.2 
1.0 

1.0 

0.0 
.0 
.0 
.0 

The  city  of  Dresden,  Germany,  has  installed1  a  manganese-remov- 
al plant,  in  which  the  water  is  filtered  through  a  growth  of  manga- 
nese-depositing microorganisms  that  remove  the  manganese  from  the 
water.  No  microorganisms  of  this  character  could  be  detected  by 
microscopic  examination  of  the  filter  sand  and  the  sediment  in  the 
wash  water  from  the  plant  at  Anna.  In  order  to  test  the  possibility 
of  their  significance  in  the  removal,  however,  some  of  the  black  sand 
which  had  been  in  use  for  several  months  and  was  removing  the  man- 
ganese was  sterilized  in  the  autoclave.  A  filter  was  prepared  from 

TABLE  39. — REMOVAL  OF  MANGANESE  BY  FILTRATION  OF  A  SOLUTION 

OF  5  PARTS  PER  MILLION  OF  MANGANESE  IN  DISTILLED  WATER  THROUGH 
AN  EXPERIMENTAL  FILTER  OF  STERILIZED  USED  SAND. 

[Parts  per  million  of  manganese.] 


Raw  water. 

Water  filtered  through- 

Unused  sand. 

Used  sand  sterilized. 

5.0 
5.0 
5.0 
5.0 

4.8 
5.0 
5.0 
5.0 

0.0 
.0 
.0 
.0 

,  D.,  Die  Entmanganung  des  Grundwassers  im  Elbtale  und  die  fur  Dresden 
ansgefuhrten  Anlagen:  J.  Gasbel.,  67,  944-8,  956-9    (1914). 


60 


MANGANESE  IN  WATER  SUPPLIES 


this  sterilized  sand,  and  after  it  had  been  washed  until  it  was  free 
from  manganese  it  was  used  to  filter  a  solution  of  5  parts  per  mil- 
lion of  manganese  as  MnS044H20  in  distilled  water.  The  results, 
in  Table  39,  show  that  complete  removal  of  manganese  was  obtained 
by  filtration  through  the  sterilized  sand. 

The  results  of  these  experiments  prove  conclusively  that  the  de- 
posit of  manganese  dioxide  on  the  grains  of  sand  effects  the  removal 
of  manganese.  The  deposit,  however,  has  been  formed  gradually  by 
the  slow  deposition  of  manganese  from  the  manganese-bearing  water 
assisted  by  direct  oxidation  by  the  dissolved  oxygen.  The  large 
amount  of  dissolved  oxygen  always  present  in  the  raw  water  evident- 
ly oxidizes  the  lower  oxide  of  manganese  to  the  dioxide  at  the  time 
the  manganese  is  removed.  The  process  is,  therefore,  catalytic  and  no 
regeneration  is  necessary.  When  the  filter  is  washed  the  grains  of 
sand  are  stirred  up,  and  the  friction  probably  is  sufficient  to  scour  off 
the  coating  of  manganese  dioxide  sufficiently  to  prevent  difficulty  in 
operation  of  the  plant. 

REMOVAL  OF  MANGANESE  AT  MOUNT  VERNON 

Mount  Vernon,  a  city  of  approximately  8,000  population,  is  in 
the  central  part  of  Jefferson  County,  Illinois.  The  water  supply  is 

TABLE  40. — MINERAL  ANALYSES  OF  THE  WATER  SUPPLY  OF  MOUNT 
VERNON. 

[Parts  per  million.] 


Casey  Fork. 

Reservoir. 

IONS 

7  6 

8  3 

Sodium   (Na) 

9  3 

13  1 

10  0 

17  6 

Calcium    (Ca)                                     ..... 

13  2 

23  3 

Iron    (Fe)         

1 

1  6 

Manganese   (Mn)  

Trace 

1  15 

Alumina    (AlzOs)  

2  0 

1  0 

Silica   (SiO2) 

174. 

7  0 

Nitrate  (NOs) 

6  0 

2  7 

Chlorine   (Cl) 

3  0 

5  0 

Sulphate  (SO4)    

62  1 

130  8 

Bases   

5  4 

3  8 

HYPOTHETICAL   COMBINATIONS 
Potassium  nitrate  (KNOs)  

9  8 

4  4 

Potassium  chloride   (KCl  )  

6  3 

10  5 

Potassium  sulphate   (KaSOO  

g 

2  2 

Sodium  sulphate  (Na2SO4) 

28  7 

40  0 

Magnesium  sulphate  (MgS04)           .             .... 

49  4 

87  0 

Calcium  sulphate  (CaSC-4)  

3  5 

45  8 

Calcium  carbonate  (CaCOs)  

30  5 

24  5 

Iron  carbonate  (FeCOs)  

2 

3.3 

Manganese  carbonate  (MnCOs) 

Trace 

2  3 

Alumina   (AhOs)  

2  0 

1  0 

Silica   (SiO2>  

17  4 

7.0 

5  4 

3.8 

Total  

154.1 

231.8 

REMOVAL  OF  MANGANESE  AT   MOUNT  VERNON 


61 


TABLE  41. — CONTENT  OF  MANGANESE  OF  RAW  AND  FILTERED  WATER 
AT  MOUNT  VERNON. 

[Parts  per  million.] 


Date. 

Raw 
water. 

Filtered        1 
water. 

Date. 

Kaw 

water. 

Filtered 
water. 

1914 

1915 

Jan.    9 

0.4 

0.2 

Feb.  16 

0.4 

0.0 

Feb.  16 

.4 

.25 

18 

.5 

.1 

Mar.  24 

.5 

.1 

20 

.4 

.0 

July  23 

.05 

.05 

23 

.5 

.0 

Aug.  18 

.12 

.12 

25 

.5 

.0 

Oct.  14 

.0 

28 

.4 

.0 

Dec.    2 

.0 

Mar.    2 

.4 

.1 

5 

.0 

4 

.4 

.1 

7 

.0 

6 

.4 

.      •     .1 

9 

.0 

15 

.4 

.0 

11 

.0 

18 

.4 

.1 

14 

.6 

.2 

20 

.3 

.0 

16 

.6 

.2 

23 

.3 

.0 

19 

.7 

.1 

25 

.3 

.0 

21 

.7 

.2 

27 

.3 

.0 

23 

.8 

.1 

29 

.3 

.0 

26 

.6 

.0 

31 

.2 

.0 

28 

.6 

.1 

31 

.6 

.1 

1915 

Jan.    4 

.6 

.1 

Apr.    2 

.3 

.1 

6 

.6 

.1 

5 

.2 

.0 

9 

.6 

.0 

6 

.2 

.0 

12 

.7 

.1 

8 

.2 

.0 

*  13 

.7 

.2 

10 

.2 

.0 

15 

.8 

.2 

12 

.2 

.0 

18 

.8 

.3 

13 

.2 

.0 

22 

.8 

.3 

16 

.2 

.0 

23 

.8 

.2 

17 

.2 

.0 

25 

.7 

.1 

22 

.3 

.0 

27 

.7 

.0 

24 

.3 

.0 

29 

.6 

.0 

Feb.    1 

.6 

.1 

3 

.6 

.2 

6 

.6 

.1 

9 

.4 

.0 

12 

.4 

.0 

15 

.4 

.0 

1 

obtained  chiefly  from  an  impounding  reservoir  fed  by  springs  in  the 
bottom,  but  Casey  Fork,  a  branch  of  Big  Muddy  River,  furnishes  an 
auxiliary  supply.  Water  from  an  impounding  reservoir  on  Casey  Fork 
is  pumped  into  the  reservoir  which  is  fed  by  springs.  The  mineral  char- 
acter of  these  two  supplies  is  shown  by  the  analyses  in  Table 
40.  Both  supplies  have  a  high  percentage  of  saturation  with  dissolved 
oxygen.  The  water  is  treated  with  about  one-half  grain  per  gallon  of 
alum.  After  sedimentation  it  is  treated  with  calcium  hypochlorite  at 
the  rate  of  0.2  to  0.3  part  per  million  of  available  chlorine.  Three 
concrete  filters,  each  having  a  capacity  of  500,000  gallons  a  day,  oper- 
ate at  a  rate  of  125,000,000  gallons  per  acre  per  day. 

The  results  of  determinations  of  manganese  made  in  the  raw  and 
in  the  filtered  water  from  January,  1914,  to  April,  1915,  are  shown 
in  Table  41.  The  determinations  after  December  1,  1914,  were  made 
in  the  laboratory  of  the  waterworks  at  Mount  Vernon.  The  content 


62  MANGANESE  IN  WATER  SUPPLIES 

of  manganese  of  the  untreated  water  varied  rather  widely,  the  range 
having  been  from  0.05  to  0.8  part  per  million  during  one  year.  The 
efficiency  of  removal  of  manganese  is  well  shown  by  comparison  of 
the  contents  of  the  raw  and  filtered  waters.  The  content  of  manga- 
nese of  the  filtered  water  has  ranged  from  0.0  to  0.3  part  per  million. 
No  manganese  was  found  in  the  filtered  water  on  35  of  the  65  days  on 
which  tests  were  made. 

The  filter  sand  was  coated  with  a  dark  colored  substance,  which 
contained  a  large  amount  of  manganese.  The  results  of  the  analysis 
of  the  sand  are  shown  in  Table  42.  When  the  sand  was  examined 
microscopically  before  being  washed  no  Crenothrix  or  similar  organ- 
isms were  found.  The  wash  water  contained  clay,  dirt,  inert  matter, 
diatoms,  chlorophyl-bearing  algae,  debris,  and  similar  material. 

TABLE  42. — ANALYSIS  OF  FILTER  SAND,  MOUNT  VERNON. 

Insoluble  in  hydrochloric  acid  99.01 

Soluble  in  hydrochloric  acid 99 

Loss  on  ignition   .43 

The  soluble  portion  consists  of: 

Ferric  oxide  (FeaO8)    4.8 

Alumina  (A12O,)   27.7 

Manganese  dioxide  (MnO2)    35.0 

Loss  on  ignition 43 

The  filter  medium  used  at  this  plant  is,  therefore,  similar  to  that 
used  at  Anna  State  Hospital.  As  the  incrustation  of  the  sand  is  not 
so  great  its  content  of  manganese  dioxide  is  somewhat  smaller.  This 
fact  probably  explains  the  somewhat  lower  efficiency  of  removal  at 
Mount  Vernon  compared  with  that  obtained  at  Anna  State  Hospital. 
The  removal  is  effected,  however,  in  exactly  the  same  process  as  at 
the  hospital,  namely,  by  filtration  through  sand  coated  with  a  layer 
of  manganese  dioxide,  which  effects  the  removal. 

INCRUSTATION"  OF  WATER  PIPES  BY  MANGANESE-BEARING  WATERS 

The  fact  that  water  which  carries  only  a  small  amount  of  man- 
ganese will  cause  serious  incrustation  of  water  pipes  has  been  noted 
by  many  investigators.  The  incrustations  consist  cjhiefly  of  oxides  of 
manganese  and  iron.  Weston1  gives  analyses  of  three  such  incrusta- 
tions, collected  from  the  water  mains  at  Hanover,  Germany  and 
analyzed  by  him.  The  largest  amount  of  manganese  present  was  7.15 

1Weston,   R.    8.,  The  purification  of  ground  waters   containing  iron   and  manganese: 
Trans.  Am.  Soc.  C.  E.,  64,  112-81  (1909). 


INCRUSTATION  OF  WATER  PIPES  63 

per  cent.  Raumer1  found  an  incrustation  in  the  water  supply  of 
Fiirth  which  contained  43.85  per  cent  of  Mn304,  equivalent  to  10.52 
per  cent  of  manganese.  The  raw  water  contained  2  parts  per  million 
of  manganese.  Threadlike  organisms  resembling  Crenothrix  were 
found.  Other  examples  of  the  clogging  of  pipes  by  manganese  waters 
are  noted  by  Bailey,2  Jackson,3  Beythien,  Hempel,  and  Kraft,4  Vol- 
mar,5  and  others.  Most  of  these  investigators  attribute  the  deposi- 
tion to  the  growth  of  iron-  and  manganese-secreting  bacteria  which 
deposit  the  oxides  of  these  metals  in  their  sheaths. 

Similar  incrustations,  whose  composition  is  reported  by  Bartow 
and  Corson,6  have  caused  serious  difficulty  in  the  water  supplies  of 
Mount  Vernon  and  Peoria,  Illinois.  In  a  microscopic  examination  of 
these  deposits  no  organisms  resembling  Crenothrix  could  be  found. 
Specimens  from  the  water  mains  of  Mount  Vernon,  Peoria,  Anna, 
and  Springfield  contained  large  amounts  of  iron  and  manganese,  but 
none  of  the  oxide-depositing  bacteria.  These  incrustations,  moreover, 
did  not  present  the  thread-like,  filamentous  appearance  which  is 
usually  characteristic  of  growths  of  Crenothrix. 

In  view  of  the  important  catalytic  effect  of  manganese  dioxide 
in  processes  of  removal  it  seems  probable  that  this  substance  is  re- 
sponsible for  the  formation  of  the  incrustations  where  organisms  do 
not  play  a  part.  If  a  manganese-bearing  water  containing  dissolved 
oxygen  is  pumped  into  the  distribution  system  there  is  undoubtedly 
a  very  slight  precipitation  of  manganese  as  the  hydrated  dioxide. 
This  dioxide  then  reacts  with  the  manganous  compound  in  the  water 
and  removes  it  as  a  lower  oxide.  The  dissolved  oxygen  present,  how- 
ever, simultaneously  oxidizes  this  lower  oxide  to  manganese 
dioxide.  The  process  is,  therefore,  catalytic,  and  is  exactly 
the  same  as  that  occurring  in  the  removal  of  manganese  in 
a  manganese-dioxide  filter.  As  acid  is  formed  as  one  of  the 
products  of  reaction  when  manganese  is  removed  the  hydrogen-ion 
concentration  of  the  water  determines  the  point  at  which  equilibrium 
is  reached.  Free  carbon  dioxide  in  solution  renders  water  acid.  So- 


aRaumer,  E.  von,  Ueber  das  Auftreten  von  Eisen  und  Mangan  in  Wasserleitungswasser: 
Z.  anal.  Chem.,  42,  590-602  (1903). 

2Bailey,  E.  H.  S.,  Occurrence  of  manganese  in  a  deposit  found  in  city  water  pipes: 
J.  Am.  Chem.  Soc.,  26,  714-5  (1904). 

'Jackson,  D.  D.,  The  precipitation  of  iron,  manganese,  and  aluminum  by  bacterial 
action:  J.  Soc.  Chem.  Ind.,  21,  681-4  (1902). 

4Beythien,  A.,  Hempel,  H.,  and  Kraft,  L.,  Beitrage  zur  Kenntnis  des  Vorkommens  von 
Crenothrix  Polyspora  in  Brunnenwassern :  Z.  Nahr.  Genussm.,  7,  215-21  (1904). 

5Vollmar,  D.,  Die  Entmanganung  des  Grundwassers  im  Elbtale  und  die  fur  Dresden 
ausgefiihrten  Anlagen:  J.  Gasbel.,  57,  944-8,  956-9  (1914). 

•Corson,  H.  P.,  Occurrence  of  manganese  in  the  water  supply  and  in  an  incrustation 
in  the  water  mains  at  Mount  Vernon,  Illinois:  Illinois  Univ.  Bull.,  Water-Survey  Series 
10,  57-65  (1913). 


64  MANGANESE  IN  WATER  SUPPLIES 

dium,  calcium,  and  magnesium  bicarbonates,  on  the  other  hand,  render 
water  alkaline  because  they  are  hydrolyzed.  Both  carbon  dioxide  and 
bicarbonate  are  usually  present,  and  whether  a  water  is  acid  or  alkaline 
depends  on  the  relative  amounts  of  each  in  the  solution.  It  is  clear 
that  the  lower  the  content  of  free  carbon  dioxide  and  the  higher  the 
content  of  bicarbonate,  the  lower  will  be  the  hydrogen-ion  concentra- 
tion, and,  therefore,  the  greater  the  tendency  toward  precipitation  of 
manganese. 

CONCLUSION 

The  results  of  the  researches  and  experimental  investigations  con- 
ducted by  the  writer  on  manganese  in  water  and  described  herein  are 
summarized  in  the  following  paragraphs. 

The  persulphate  method  is  the  most  convenient  and  accurate 
method  for  the  colorimetric  determination  of  manganese  in  water. 
Chloride  does  not  interfere.  Five-thousandths  of  a  milligram  of  man- 
ganese in  a  volume  of  50  cubic  centimeters,  equivalent  to  0.1  part 
per  million,  can  be  detected. 

The  standardized  bismuthate  method  is  accurate  and  reliable. 
The  presence  of  chloride  in  amounts  less  than  5  milligrams  does  not 
interfere  with  this  determination.  By  this  method  0.01  milligram  of 
manganese  in  a  volume  of  50  cubic  centimeters,  equivalent  to  0.2  part 
per  million,  can  be  detected. 

The  lead-peroxide  method  gives  too  low  results  because  of  reduc- 
tion of  permanganate  in  using  the  Gooch  crucible.  The  presence  of 
chloride  interferes  in  this  method  more  seriously  than  in  either  of  the 
others,  and  if  more  than  5  milligrams  of  chloride  are  present  no  man- 
ganese may  be  found  even  if  a  comparatively  large  amount  is  present. 
This  method  is  at  best  the  least  sensitive  of  the  three,  and  it  should 
be  rejected  as  a  standard  method. 

Manganese  occurs  normally  in  certain  classes  of  water  in  Illinois, 
and  amounts  sufficient  to  affect  the  quality  have  been  found  in  several 
waters. 

Little  manganese  is  present  in  water  from  ' '  Potsdam ' '  sandstone, 
St.  Peter  sandstone,  the  overlying  limestones,  Lake  Michigan,  and  the 
large  rivers. 

Manganese  is  usually  present  in  large  amounts  in  coal-mine 
drainage,  in  water  from  some  impounding  reservoirs  on  small  streams 
in  southern  Illinois,  and  in  water  from  some  wells  entering  uncon- 
solidated  deposits  near  rivers.  No  apparent  relation  exists  between 
the  content  of  manganese  of  a  water  and  any  of  the  other  mineral 
constituents. 


CONCLUSION-  .-/-•;..:     V :  **',  \  ^  ]  ]  • '-,  65 

The  principle  underlying  all  processes  for  the  removal  of 
manganese  from  water  supplies,  except  those  of  direct  chemical  pre- 
cipitation, is  the  reaction  between  manganous  compounds  and  manga- 
nese dioxide  to  form  a  lower  oxide. 

The  removal  of  manganese  by  the  permutit  process  takes  place 
according  to  this  reaction,  as  the  state  of  oxidation  of  manganese  in 
the  substance  is  not  greater  than  that  in  manganese  dioxide.  This  is 
in  agreement  with  the  view  of  Tillmans.  No  evidence  of  the  existence 
of  oxides  higher  than  Mn02  in  this  substance  was  found  by  the  writer, 
contrary  to  the  suggestion  of  Gans  and  the  Permutit  Co. 

No  appreciable  removal  of  manganese  was  obtained  on  an  experi- 
mental scale  by  aeration  and  sand  nitration,  as  reported  by  Thiesing, 
Weston,  and  Barbour.  When  an  artificial  coating  of  manganese 
dioxide  was  prepared  on  the  grains  of  sand,  however,  complete  re- 
moval of  manganese  was  obtained.  Manganese  is  efficiently  removed 
from  water  supplies  at  Anna  and  Mount  Vernon,  Illinois,  by  this 
process,  a  coating  of  manganese  dioxide  having  formed  on  the  sand. 
If  the  water  contains  dissolved  oxygen  regeneration  of  the  filter  is 
unnecessary,  and  the  process  may  be  considered  catalytic. 

The  success  of  the  aeration  and  sand-filtration  process  used  by 
Thiesing,  Weston,  and  Barbour  is  in  reality  due  to  the  action  of  man- 
ganese dioxide  and  not  to  aeration  and  sand  filtration  alone.  The  as- 
sumption that  manganese  may  be  removed  by  the  same  process  which 
removes  iron  is  incorrect. 

The  formation  of  incrustations  of  manganese  in  water  pipes, 
where  manganese-secreting  bacteria  are  not  present,  is  explainable  by 
the  catalytic  action  of  manganese  dioxide. 


VITA 

The  writer  received  his  early  education  in  the  public  schools  of 
Concord  and  Laconia,  New  Hampshire.  He  was  graduated  with  the 
the  degree  of  Bachelor  of  > Science  from  New  Hampshire  College  in 
1910.  He  received  the  degree  of  Master  of  Science  from  the  Uni- 
versity of  Illinois  in  1912. 

He  was  assistant  in  chemistry  from  1910  to  1911  and  assistant 
in  sanitary  chemistry  from  1911  to  1915  in  the  University  of  Illinois. 
He  was  chemist  in  the  Illinois  State  Water  Survey  from  1911  to  1912 
and  chemist  and  bacteriologist  of  the  same  survey  from  1912  to  1915. 

His  publications  are : 

With  Charles  L.  Parsons, 

The  solubility  of  barium  nitrate  and  barium  hydroxide  in 
the  presence  of  each  other :  J.  Am.  Chem.  Soc.,  32,  1383-7 
(1910). 

With  Edward  Bartow, 

Methods  of  analyzing  chemicals  used  in  water  purifica- 
tion. Proc.  111.  Water-Supply  Assoc.,  3,  114-29  (1911). 

With  Edward  Bartow, 

The  occurrence  of  manganese  in  the  water  supply  and  in 
an  incrustation  in  the  water  mains  at  Mount  Vernon, 
Illinois:  Illinois  Univ.  Bull.,  State  Water-Survey  Series 
10,  56-65  (1913). 


66 


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